An evil spirit called Cryto

 "An evil spirit called Cryto is killing off members of a wealthy family. One of them, baby Matthew, is sent to Halliwell Manor by his mother for protection.

The three Halliwell sisters unexpectedly become… reluctant nannies. Piper panics because she is not used to taking care of children, Phoebe finds herself fond of baby Matthew, and Prue – strong and serious – begins to show a tender attachment to the baby.

At the same time, they try to figure out why Cryto is targeting the family, and how to destroy him. Through investigation, they discover that Cryto was once sealed away by that family, and he is seeking revenge.

Prue is especially moved when she sees baby Matthew abandoned to be saved, reminding her of herself – who was also hidden away by her mother to protect her from evil.

Finally, the three sisters join forces to destroy Cryto with a powerful spell, and baby Matthew is reunited with his mother in loving arms."