Lotor is given a potion that turns plants into evil beasts. His visit with Dooms resident chemist is cut short when he's alerted to his father's failing health. Zarkon appears to be dying, and while Haggar prays to the Dark Spirits, Lotor goes to Arus for some berries that are needed to save Zarkon. Allura just happens to be out in the forest picking berries with her maids when Lotor arrives. He uses the potion to transform some trees into horrifying beasts. The women scream and huddle in horror. When the boys on the team see vultures circling over the forest, they're worried about the Princess. Just when Lotor tries to move in and take the Princess, Keith beats him to it by swinging down on a vine and carrying her to safety. The rest of the team does likewise for the other terrified women. Once the women are safe, the team fetch the Lions.
When the tree beasts fail against Voltron, Lotor returns to Doom. With a potion spiked with cobra venom, he presents it to Zarkon as the magic cure. Zarkon guzzles it down and Lotor is disappointed it doesn't finish him off - the King is back healthier than ever.