The world is in lockdown, and Jack has been stuck at home for what feels like an eternity. When he discovers a mysterious tunnel under his bed, an amazing adventure unfolds for Jack and his little sister, Lily. Together, they discover a magical forest, stop a powerful crystal from falling into the wrong hands, travel to the ends of the galaxy, and fight a gang of mutant hyenas. Along the way, they are joined by Winston, the Tortoise, and Dougie, a Mole whose superb tunneling skills might just save the day. Or could the secret weapon be a stinky cheese sandwich stuffed inside a pair of underpants?