Immerse kids in the ultimate augmented-reality play experience with this exciting LEGO® Hidden Side™ 70421 Ghost Train Express playset. This awesome toy combines a buildable LEGO model with an augmented reality app to deliver a fully interactive play experience. Download the Hidden Side app and scan the model with a phone to make it come alive – interacting with the model makes things happen in the app. And with continuous updates, a unique boss ghost to battle in each set, new mysteries to solve, cool items to find, games to play and ghosts to collect, this LEGO Hidden Side set gives kids a whole new way to play and interact with LEGO bricks! This awesome train playset features cool, high-tech, ghost-catching details to inspire hours of imaginative play. And with 5 minifigures, including heroes Jack and Parker, there are a lot of play-starters so the action can start right away.