The LEGO Hidden Side magazine gift sets were small LEGO sets that were included as promotional items with the LEGO Hidden Side Magazine. These sets typically contained a limited number of pieces and instructions for a simple build, often tied to a Hidden Side related theme or character highlighted in the magazine. They served as an incentive for magazine purchases and offered LEGO enthusiasts a supplementary building experience.
The LEGO Hidden Side theme was introduced in the summer of 2019 that was tech influenced and included a storyline and an app game (Apple App Store and Google Play). The theme is focused around the haunted town of Newbury and is designed with an augmented reality (AR) app, allowing users to capture ghosts while solving mysteries within the spooky town.
From the LEGO official description: "Forget what you know – you’ve never experienced LEGO© play like this before. Your phone opens the door to a virtual hidden world where your LEGO© sets come alive in an unfolding ghostly adventure. Solve the mysteries haunting the town of Newbury before it’s too late."