Top Biggest LEGO Hidden Sets ever

The LEGO Hidden Side theme revolutionised the building experience by merging physical LEGO sets with augmented reality technology. This groundbreaking series, which ran from 2019 to 2020, transported builders to the fictional town of Newbury, where teenage ghost hunters Jack and Parker battled supernatural forces using both traditional building play and AR mobile apps.

Hidden Side delivered some truly massive, complex builds that pushed the boundaries of LEGO design. These sets featured mechanical changes between normal and haunted states, detailed interiors, and enough pieces to satisfy even the most demanding builders.

Let's explore the biggest and most impressive sets from this beloved theme, ranked by piece count and overall building experience.

How Do Two Teenagers Save an Entire Town from Ghosts?

The Hidden Side story centres on the coastal town of Newbury, where ghostly spirits have invaded everyday locations. Heroes Jack Davids and Parker L. Jackson, armed with special smartphones, discover they can see and battle these supernatural entities through AR technology.

Each set in the line serves a dual purpose. Builders can enjoy traditional LEGO construction and play, then enhance their experience with the free Hidden Side app. The app reveals hidden ghosts, animations, and interactive elements when scanning built models with compatible iOS and Android devices.

This theme addressed previous AR missteps from LEGO Playgrounds by ensuring broader device compatibility and more engaging gameplay. The result was a cohesive universe where every set contributed to an overarching narrative while standing strong as individual builds.

1. 70425 Newbury Haunted High School (1,474 Pieces) (Amazon)

The Newbury Haunted High School stands as the undisputed champion of LEGO Hidden Side sets. With 1,474 pieces and 8 minifigures, this massive educational institution changes from an ordinary school into a supernatural hotspot.

Building Experience and Features

This multi-story behemoth showcases incredible attention to detail. The school features fully furnished classrooms, a functional bathroom, cafeteria areas, and even outdoor elements like lamp posts and playground equipment. The modular design allows builders to explore different sections independently.

The mechanical shifting is particularly impressive. Various parts of the school "gloom" when activated, revealing hidden supernatural elements. Windows flip to show spooky interiors, walls rotate to expose ghostly chambers, and the iconic monster face emerges from the roof structure.

Minifigures and Accessories

The set includes key characters Rose Davids, Jack Davids, Paola, Mr. Clarke, Parker L. Jackson, and Wade, plus Spencer the ghost dog. Additional elements include skeletons, spiders, bears, and various school furniture pieces that enhance both play value and display appeal.

AR Integration

When scanned with the Hidden Side app, the school comes alive with animated ghosts, moving elements, and interactive challenges. The AR experience here is among the most complete in the entire theme, with multiple scan points triggering different supernatural events.

Price Point: Originally retailed for approximately $129.99, offering excellent value given the piece count and complexity.

2. 70437 Mystery Castle (1,035 Pieces) (Buy online)

The Mystery Castle delivers medieval menace with 1,035 pieces of Gothic architecture and supernatural storytelling. This imposing fortress represents the Hidden Side theme's venture into classic horror territory.

Architectural Marvel

The castle features multiple towers, interconnected chambers, and a sprawling base that includes caves and underground passages. The design brilliantly balances medieval authenticity with Hidden Side's signature mechanical features.

Key architectural elements include stained glass windows (some of the finest ever produced in LEGO), ornate facades, and a trap door mechanism that drops unsuspecting visitors into the tentacled grasp of lurking monsters below.

Mechanical Features

The castle's "glooming" reveals hidden chambers filled with supernatural elements. Walls slide away to expose ghost-infested rooms, towers rotate to show different interior configurations, and various mechanical elements create dynamic play scenarios.

Notable Characters

This set introduces exclusive minifigures, including castle inhabitants and spectral entities unique to this location. The character selection enhances both the medieval setting and the overarching Hidden Side narrative.

Value Proposition: At $99.99 original retail, this set offered substantial building satisfaction and display presence, making it a favourite among both Hidden Side enthusiasts and castle collectors.

3. 70436 Phantom Fire Truck 3000 (760 Pieces) (Amazon)

The Phantom Fire Truck 3000 combines emergency vehicle aesthetics with sci-fi changing capabilities. This 760-piece set showcases Hidden Side's ability to reimagine everyday vehicles as supernatural-fighting machines.

Engineering Excellence

The fire truck features authentic emergency vehicle detail, including ladder assemblies, equipment compartments, and realistic cab interiors. What sets it apart is the rear section's ability to change into a fully articulated mech robot.

The conversion sequence is elegantly engineered. The truck's rear unfolds to form mech legs and feet, while the main cannon becomes a cockpit. This modular approach allows quick deployment without complex rebuilding.

Unique Design Elements

The truck incorporates dark azure armour plating, specialised weaponry, and scanning elements that trigger AR events. Interior details include control panels, equipment storage, and seating for multiple minifigures.

Character Roster

The set includes Jack, Parker, J.B., TeeVee, and Shadow-Walker minifigures, plus the imposing Nehmaar Reem - The Harbinger figure. This villain stands over 6 inches tall and represents one of Hidden Side's most impressive brick-built characters.

AR Combat Experience

The app changes this set into a mobile command centre for ghost battles. The AR experience includes dynamic chase sequences and boss battles against the fire-themed ghost Blaze M. Barr.

Design Recognition: Created by Niek van Slagmaat (also designer of LEGO Ideas Voltron), this set showcases sophisticated engineering and creative part usage.

4. 70424 Ghost Train Express (698 Pieces) (Amazon)

The Ghost Train Express captures the romance and mystery of classic locomotives while delivering supernatural thrills. This 698-piece set proves that Hidden Side could tackle any vehicle type with style and innovation.

Locomotive Authenticity

The train features detailed engine components, passenger cars, and authentic railway elements. The design respects real locomotive proportions while incorporating Hidden Side's signature supernatural modifications.

Key features include functional doors, detailed interiors, and mechanical elements that enhance both display value and playability. The train's length and presence make it an impressive centrepiece for any collection.

Supernatural Elements

The mechanical shifting reveals ghostly passengers, haunted compartments, and spectral effects throughout the train cars. These elements integrate seamlessly with the locomotive's realistic details. Many builders enhance their displays with lightning accessories to amplify the supernatural atmosphere during exhibitions.

Track and Station Elements

While primarily focused on the train itself, the set includes track pieces and station elements that expand the play environment and provide context for the railway setting.

Historical Significance: This represents one of the few modern LEGO train sets available outside the dedicated train system, making it particularly valuable for railway enthusiasts.

5. 70423 Paranormal Intercept Bus 3000 (689 Pieces) (Amazon)

The Paranormal Intercept Bus 3000 changes the iconic American school bus into a high-tech ghost-hunting laboratory. With 689 pieces, this set showcases Hidden Side's talent for reimagining everyday vehicles.

School Bus Authenticity

The bus maintains classic yellow school bus proportions and design elements while incorporating sophisticated ghost-hunting equipment. The eight-stud-wide construction provides substantial presence and realistic scale.

Mobile Laboratory Features

The rear section slides out to reveal a complete command centre with computer terminals, analysis equipment, and seating areas. This mobile lab concept perfectly suits the teenage protagonists' ghost-hunting adventures.

Character Integration

The set includes heroes Jack and Parker, tech specialist J.B., plus construction workers Nanna and Bill. The character selection reflects Hidden Side's approach of populating Newbury with diverse residents affected by supernatural events.

Easter Eggs and References

The set contains numerous references to classic LEGO themes, including Rock Raiders and Bionicle, demonstrating the designers' appreciation for LEGO history and fan service.

Play Value: The combination of vehicle, laboratory, and character elements creates multiple play scenarios, from ghost-hunting missions to everyday school transportation.

6. 70422 Shrimp Shack Attack (579 Pieces) (Amazon)

The Shrimp Shack Attack brings seaside dining into the supernatural sphere with 579 pieces of detailed restaurant construction and aquatic adventure elements.

Restaurant Details

The shrimp shack features complete kitchen facilities, dining areas, and outdoor seating that capture the atmosphere of coastal dining establishments. The attention to culinary details enhances both realism and play value.

Mechanical Elements

The restaurant's supernatural shifting reveals hidden ghostly elements throughout the structure. Kitchen equipment becomes possessed, and dining areas change into haunted spaces.

Aquatic Elements

The set includes boat elements and water-themed accessories that expand the play environment beyond the restaurant structure. These elements connect to Hidden Side's coastal Newbury setting.

Character Diversity

The minifigure selection includes restaurant staff, customers, and supernatural entities, creating a complete cast for dining and ghost-hunting scenarios.

7. 70431 The Lighthouse of Darkness (540 Pieces) (Amazon)

The Lighthouse of Darkness rounds out our list with 540 pieces of maritime mystery. This coastal sentinel showcases Hidden Side's ability to create atmospheric builds that serve both practical and supernatural purposes.

Lighthouse Construction

The lighthouse features authentic maritime architecture, including the lamp room, keeper's quarters, and rocky foundation elements. The vertical construction creates impressive height and visual impact.

Rocky Base and Caves

The set's foundation includes cave systems, rocky outcroppings, and dock elements that provide additional play areas and enhance the coastal atmosphere.

Maritime Characters

The character selection includes lighthouse keeper Claus Stormward, diver Jennie Napo, and various supernatural entities that populate this haunted coastal location.

Atmospheric Design

The combination of lighthouse, rocks, and water elements creates one of Hidden Side's most atmospheric settings, perfect for storytelling and display.

Why Do These Sets Feel Far Superior to Today's Releases?

The Hidden Side theme succeeded by combining several key elements that set it apart from other LEGO lines. Each LEGO Hidden Side review consistently highlights these innovative features:

• Scale and Complexity: These sets pushed piece counts higher than many comparable themes, offering substantial building challenges and impressive completed models.
  
  
• Dual Play Experiences: The integration of traditional LEGO play with AR technology created unique value propositions that appealed to different age groups and play preferences.
  
  
• Mechanical Features: Each set included mechanical elements that revealed hidden supernatural aspects, adding discovery and surprise to the building experience.
  
  
• Character Development: The consistent cast of characters and ongoing narrative created emotional investment that encouraged collecting multiple sets.
  
  
• Design Innovation: The theme encouraged creative part usage and unconventional building techniques that resulted in memorable and distinctive models.

What Secret Technologies Were Too Advanced for 2020 Release?

When Hidden Side production ended in 2020, its influence on LEGO construction philosophy and play mechanics persisted far beyond its brief run. The successful merger of digital technology with traditional brick-building established new benchmarks that shaped later product lines, while original sets maintain strong demand within collecting communities worldwide.

This experimental line demonstrated LEGO's capacity for pushing creative boundaries without abandoning the fundamental hands-on construction principles that built the company's reputation. High piece counts paired with mechanical elements and engaging narrative frameworks delivered satisfaction across diverse builder demographics, from weekend hobbyists to dedicated AFOL communities.

Enthusiasts hunting these distinctive builds now turn to reseller networks and auction platforms, where discontinued status and expanding collector appreciation have driven valuations significantly above original retail pricing structures.

FAQ

What made LEGO Hidden Side different from other themes?

LEGO Hidden Side combined traditional building with augmented reality technology through a mobile app. When you scanned completed models with the app, hidden ghosts and animations appeared, creating an interactive digital layer over the physical builds. This dual-play experience was unprecedented in LEGO history.

Are Hidden Side sets still available to purchase?

The Hidden Side theme was discontinued in 2020, so new sets are no longer available through official LEGO retailers. However, you can find these sets through secondary markets, speciality LEGO stores, and online marketplaces, though prices may be higher than original retail.

Do you need the app to enjoy Hidden Side sets?

Absolutely not! While the AR app enhanced the play experience, each LEGO Hidden Side set functions perfectly as a traditional building toy. The sets feature mechanical shifting mechanisms, detailed interiors, and excellent minifigures that provide plenty of entertainment without digital enhancement.

Which Hidden Side set offers the best value for beginners?

The Paranormal Intercept Bus 3000 provides excellent value with its substantial build, multiple play features, and iconic school bus design that works well beyond the Hidden Side theme. It offers a complete experience without requiring the largest investment.

Can Hidden Side sets integrate with other LEGO themes?

Yes! Many Hidden Side sets, particularly vehicles like the Phantom Fire Truck 3000 and Paranormal Intercept Bus 3000, can easily fit into LEGO City layouts. The buildings work well in any town setting, and the minifigures are compatible with all LEGO themes.

What age groups were Hidden Side sets designed for?

Most Hidden Side sets targeted ages 8 and up, though the larger sets like Newbury Haunted High School appealed to older builders and adult fans. The theme successfully bridged child and adult interests through sophisticated building techniques and nostalgic references.

Is the Hidden Side app still functional?

While the theme is discontinued, the Hidden Side app remained functional for several years after the theme ended. However, long-term app support cannot be guaranteed, so the traditional building experience is the most reliable way to enjoy these sets.

What makes the biggest Hidden Side sets worth collecting?

The largest sets, like Newbury Haunted High School and Mystery Castle, offer exceptional piece counts, complex building experiences, and impressive display presence. They represent some of the most innovative LEGO designs of their era and showcase the theme's creative peak.