When Phoebe falls prey to a demon named Jeric, who is kidnapping witches in order to find the perfect host body for his love, Isis, Cole decides to attempt to make a trade: Paige's body in exchange for Phoebe being returned safely. However, thanks to Cole's decision, Piper is able to trick Jeric in order to save both of her sisters in order to banish the demon. It is only after Cole realizes he has failed to destroy the Power of Three, he promises the sisters the next time they meet, he won't fail.
Spoilers ahead. Coverage follows the scope labeled below.
Complete story — includes the ending
Phoebe falls prey to Jeric, a demon in search of the perfect body to hold the spirit of Isis, his dead lover. To trap the spirit, Jeric mummifies Phoebe's body. Cole tries to save Phoebe by making a deal with the Jeric by exchanging Phoebe's body for Paige's. Piper tricks the demon and saves Paige who is able to free Phoebe and banish the spirit. Piper destroys the demon by blowing him up with her molecular combustion power, and Cole leaves promising to win next time.