Promotional sets are a subtheme of Hidden Side introduced in 2020 and currently consists of 3 sets. All sets were released in 2020. As of today, the average annual growth of sets in Hidden Side Promotional is approximately 11.3% per year.
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.