Set in the 1990s, Tricky begins in a London animation studio run by a husband-and-wife team famous for creating beloved cereal mascots. Their world crumbles when new regulations ban sugary ads targeted at children, effectively cancelling their entire industry overnight. The husband flees to America, leaving behind his wife and their daughter, Maya. Decades later, Maya’s 12-year-old daughter, Charli, discovers a VHS tape of the old commercials. Hoping to connect with the grandfather she’s never met, she uploads digitized clips to TikTok using AI tools. But the experiment goes horribly wrong: her viral videos open a portal between worlds, unleashing the once-cute mascots, now twisted, AI-enhanced monstrosities, into the real world.