Bloom is trying to blow up a rock while practicing her power, but can't do much damage because she isn't focusing her energy due to stress over Darkar getting two codexes, and seems to be getting weaker.
Professor Avalon sends Bloom into another virtual world, with scenes of her Earth parents, then her birth parents, then the Great Dragon. Dark smoke appears and says darkness descend upon her. Supposedly the whole trip will make her stronger. However, she feels that there is a negative force around her now. Lockette doesn't trust Avalon because the path to his heart is blocked. Bloom transforms to try out her new powers, but dark smoke appears around her and her pupils turn into slits. She turns evil and hangs Timmy upside down before returning to her original self. Avalon says she picked up a rare shadow virus and looks for a spell to remove it.
Stella gives Bloom a makeover to keep her calm and relaxed, but the shadow virus takes control again and Bloom becomes "Dark Bloom" once more. As Darkar watches, Dark Bloom enters the secret archives, where Alfea's codex is. When Dark Bloom says her intentions, Concorda shrinks her to small size, but she destroys books in search of the codex. When she threatens Concorda, the fortune fly, Nippocampus, reveals the codex to her, but keeps it from her. Eventually Dark Bloom gets it.
The other Winx arrive. Flora tries to talk some sense into Dark Bloom, but she won't listen. Stella's Solar Flare is ineffective as well. As Darkar sends Kerborg, Lockette almost gets through to Bloom, but Dark Bloom takes hold again. Taking a dark appearance, she counters the other Winx attacks and gives the codex to Kerborg. Avalon arrives and removes the shadow virus, returning Bloom to her original self. Avalon suggests that Bloom got the shadow virus from her last fight with Icy. The only thing Bloom remembers from when she was Dark Bloom is Lockette.
Kerborg gives the codex to Darkar.
- Darkar gets the third codex