When Icicle returns to enact the next phase of his devious plan, Caitlin and her mother, Dr. Carla Tannhauser, must resolve their long-combative relationship to defeat the icy monster. After Barry makes a big decision about their family without consulting her, Iris decides to take matters into her own hands.
Quest roles:
Susan Walters(Dr. Carla Tannhauser), Morena Baccarin(Gideon (voice) (uncredited)), Islie Hirvonen(Grace Gibbons), Kyle Secor(Thomas Snow / Icicle), Sarah Carter(Grace Gibbons / Cicada II), Everick Golding(Trevor Shinick), Bruce Crawford(JP Chipera)