With the memory of their harrowing escape from Nexus City still fresh in their minds, the League decides to take some well-deserved downtime in Castle Grayskull. But it turns out that even extremely well-fortified magical sanctuaries aren't completely impervious, and when an old friend and a new enemy set their sights on the Power of Grayskull, the League will have to step up to defend it... or die trying.

Nico gets lost in her reading; Mordin seeks to do the impossible three times over; Stitch finds some loose change; Helena introduces herself with cake; and Dante sounds huskier than ever.