The episode opens with Phoebe and Jason having dinner at a restaurant. After a passionate kiss, Phoebe, the empathic one, answers Jason's thoughts by saying "I love you, too". This statement freaks them both out, foreshadowing future troubles. Paige arrives to enlist Phoebe's assistance with Piper's 'power problem', only further irritating Jason as Phoebe stumbles off with her sister, leaving him alone.
After vanquishing a Manticore demon (who is feeding on the demon they intended to vanquish), the Three discover a Manticore-human hybrid baby and orb it home with them. They can't bring themselves to vanquish a baby, especially after Wyatt befriends him. Piper has taught Wyatt the 'peek-a-boo' game and the kids play it as the baby vanishes and reappears at will. Chris orbs in and wants the Charmers to vanquish 'it' immediately. Darryl calls Paige to please come help him with magic.
A creature discovers both his vanquished 'wife's' ashes and the missing babies wrap and roars his displeasure. Phoebe stomps into a closed-door meeting Jason is having at the office and is upset when she learns that he is leaving again, that very night, for Rome. She angrily accuses him of being afraid of his feelings.
Piper, the mother, can't bring herself to 'vanquish a baby'. Chris goes to fetch Leo to help convince her. Paige makes Darryl invincible so that he can talk to the kid holding the hostages without getting hurt. Bullets now bounce off of him, like Superman. Piper orders Wyatt not to orb back downstairs to be with his 'little friend', so he orbs the baby demon upstairs instead. The creature shows up when the baby starts crying and attacks Phoebe. Wyatt shields both babies from him so he disappears with Piper instead.
Phoebe tells Paige that it wasn't a Manticore that attacked, it was more 'beast-like'. Leo shows up with Chris, and Paige argues that there is nothing inherently evil about 'kids', especially this kid. As an orphan, she argues nurture over nature. Leo and Chris orb away to 'heaven' with Wyatt, while the girls cook up a another potion.
Piper, tied to a chair, converses with the creature that captured her. She breaks free but can't escape the house, so she hides. The creature threatens but can't bring himself to kill Piper. Meanwhile, Darryl emerges with his prisoner and the freed hostages, only to discover that not only is he invulnerable, but that he has super strength as well - ripping the door off his police cruiser. Back at the mansion, the baby starts crying as Phoebe argues with Jason on the telephone. Three Manticores attack. Only one is vanquished when the creature arrives and battles the other two. As he hugs the baby, Phoebe hurls a potion at him and he vanishes, taking the baby with him.
Piper finally overcomes the house's magic and opens the door, only to discover herself in a typical upper-middle neighborhood. She goes back inside to find the creature/father reassuring his baby that it's OK, he's back home now. Piper tries to heal the creature's wound while her sister's prepare to negotiate with the Manticores to get her back. The father explains how he turned himself a powerful creature to find his son and protect him from the Manticores ("I just wanted my son").
Phoebe and Paige orb in and orb out with Piper as the Manticores they brought along with them attack the father. Piper has them hurry back but the father lies dying and the baby is gone. Piper has Leo heal the creature, who is now human again. Against Chris's wishes, the Three prepare to go back. They rescue the baby by playing 'peek-a-boo' and getting him to disappear while they vanquish the Manticores.
Derek, the now human dad, leaves with his magical, half-manticore son as Darryl calls Paige, who forgot to reverse his spell. Darryl's super strength has caused him to nearly total his office. Phoebe goes to her office and discovers that Jason cancelled his flight. As they embrace and Jason says 'I love you, too', the music fades on a dark note.