A young woman named Lydia calls on the Defenders to help her when she is attacked by Amphibigors. Mel, Erik, and Adam go to help her, while Seth, Rion and Kara stay behind. While Lydia is unharmed, the Amphigors get away with her special 'Heart Stone'. She tells them that the Amphigors have her brother, and they volunteer to help her. Meanwhile, Seth tests out the new mech arm Erik has made for him, and they are suddenly attacked by the Zad. Kara defeats them with her dark new guardian and powers. Erik repairs Lydia's vehicle, but they crash when Erik and Adam (who is driving) get into a fight. Melosa is captured by Lady K'Tahsh, while Adam, Erik, and Lydia continue to pursue the Amphibigors, much to Adam's concern for Mel. Seth and Rion receive Melosa's distress call and split up. Rion goes in one direction and chases K'Tahsh, but fails when she disables his stormer with an energy whip. Adam, Erik and Lydia sneak into the Amphigor's camp to take the Heart Stone, but are interrupted when some Amphibigor warriors attack them. Seth arrives and defeats them with the new and improved mech arm, and Lydia reclaims the Heart Stone. She then decides to leave without rescuing her brother, who suddenly arrives unharmed with the Amphigor princess. He explains to Lydia that the Amphibigors were willing to share the Heart Stone's energy with their village. It turns out that Lydia is a thief, who wants the Heart Stone for her village and not the savage Amphibigors. Lydia escapes, but the Amphigors and the Defenders catch up to her. She threatens to destroy the Heart Stone with a Bakorian stone-presser. As she backs up, Lydia trips on a log and drops the stone presser, causing it to activate. Seth manages to destroy the device with Bedlam, but is struck with some of the Heart Stone's energy. The Amphibigors put the stone back in their generator, which manages to take minimal damage. Meanwhile, Kara looks for a device, and she manages to strike a deal after Brackus eavesdropped on