<Tr> <Th> 20 </Th> <Td> 20 </Td> <Td> "The Power of Two" </Td> <Td> Elodie Keene </Td> <Td> Brad Kern </Td> <Td> May 12, 1999 (1999 - 05 - 12) </Td> <Td> 4398019 </Td> <Td> N / A </Td> </Tr> <Tr> <Td_colspan="8"> The evil spirit of a serial killer (Jeff Kober) escapes from Alcatraz Island seeking revenge on his judge and jury . Phoebe and Prue must figure out how to vanquish this evil spirit and stop him from killing again without Piper, who is in Hawaii . Eventually, Prue drinks a concoction that temporarily stops her heart and vanquishes the spirit with a spell that can only be cast on the Astral Plane by a ghost before Andy revives her . </Td> </Tr> <Tr> <Th> 21 </Th> <Td> 21 </Td> <Td> "Love Hurts" </Td> <Td> James Whitmore, Jr . </Td> <Td> Chris Levinson & Zack Estrin & Javier Grillo - Marxuach </Td> <Td> May 19, 1999 (1999 - 05 - 19) </Td> <Td> 4398020 </Td> <Td> N / A </Td> </Tr> <Tr> <Td_colspan="8"> A wounded Leo appears at the manor, asking the Halliwell sisters to protect an innocent woman returning to San Francisco under his guidance . Daisy (Lisa Robin Kelly) is being stalked by a Darklighter who hunts and kills present and future Whitelighters with poisoned arrows . The Darklighter Alec (Michael Trucco) fell in love with her . Leo reveals that the Darklighter's poison is deadly, and Piper finds a power switching spell in the Book of Shadows so she can use Leo's healing power on him . Unfortunately, this has the side - effect of switching everyone's powers and they all have to try to learn to use them . While Prue and Phoebe manage to control each other's powers, Piper is unable to heal Leo and he dies . Afterwards, she admits her love for him and discovers that it is the trigger for his power and heals him . She uses his powers to track down Daisy and Prue vanquishes Alec with his own power . </Td> </Tr>

When does leo come back in season 1