Even more of a comedy story than its companion, Danger at Castle Grayskull! is a light-hearted children's adventure featuring several of the early MOTU characters. Illustrated by Alfredo Alcala, the story begins with a combat practice session between He-Man and Man-At-Arms; a workout which Teela rather stupidly interprets as a real battle. When Zoar delivers a message about Skeletor, Teela decides to take the Attak Trak, despite having been told it doesn't seem to be working very well.

The Attak Trak, it turns out, has the capacity for independent thought in this story, reacting when Skeletor tries to use the vehicle by expelling a cloud of smoke. It isn't the only vehicle used in Danger at Castle Grayskull!; the Talon Fighter is used by He-Man and Man-At-Arms to reach the fortress before Skeletor and his men arrive. The tale features Man-E-Faces who is turned into his monster personality by Skeletor in order to capture Teela.

Tri-Klops, Mer-Man and Trap Jaw are also featured. A rather weak aspect of the story is Trap Jaw suffering the effects of rust after He-Man throws water over him. After escaping confinement inside the castle, the heroes encounter Skeletor on the battlements. He-Man summons Zoar who then drops bombs on the unfortunate villain. Skeletor is blown over the top of the fortress but suffers no ill-effects other than the loss of his dignity.

As with The Power of Point Dread!, this tale fits loosely into the pre-Filmation era if not the canon. Zoar is not yet the alter-ego of the Sorceress, retaining his role as her messenger. Danger at Castle Grayskull! is a simple children's story which entertains on that level. Alcala's illustrations are colourful and enjoyable. At this stage of the development of the MOTU it was clear where the concept was going. While it is possible to enjoy the silliness of tales such as this, it's also worth remembering that it represented the demise of best incarnation of the Masters of the Universe.