Episode Title:The Heart Stone.Episode Description: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...