Children can have incredible augmented reality gaming experiences with the LEGO Hidden Side™ "Ghost Train" playset (70421). This fantastic playset with an app combines a buildable LEGO model with an augmented reality experience, providing a fully interactive gameplay experience. Download the Hidden Side app and scan the model with your smartphone to bring it to life – playing with the model triggers events in the app. Continuous updates, a unique ghost boss to defeat for each set, and new puzzles, items, and ghosts to collect – the LEGO Hidden Side set opens up entirely new possibilities for children playing with LEGO bricks! The awesome train playset features cool high-tech ghost-hunting details for hours of imaginative play. The 5 minifigures, including Jack and Parker, offer endless play possibilities – you can start right away!.