He-Man and the Masters of the Universe: The Hunt for Moss Man (Tales of Eternia Book 1)

"A mysterious toxic gas is spreading across Eternia, ravaging farmlands and endangering citizens. The planet's only hope lies with Adam, a lost prince with cosmic abilities. When he wields the mystical Sword of Power, he transforms from a scrawny teen into He-Man, the most powerful man in the universe. With his friends Teela, Cringer, Duncan, and Krass by his side, Adam embarks on a dangerous journey, facing pirates, dragons, and perils at every turn in search of Moss Man"--Back cover.