<Tr> <Td_colspan="8"> Paige, who feels like a fifth wheel among her happily married sisters and their husbands, becomes firmly convinced that Cole is still evil . Cole, the new Source, and the Seer secretly plot to impregnate Phoebe . Meanwhile, the sisters try to save a columnist as Cole tries to get Paige out of the way through his demonic contacts in The Underworld . </Td> </Tr> <Tr> <Th> 83 </Th> <Td> 17 </Td> <Td> "Saving Private Leo" </Td> <Td> John Behring </Td> <Td> Daniel Cerone & Doug E. Jones </Td> <Td> March 28, 2002 (2002 - 03 - 28) </Td> <Td> 4301083 </Td> <Td> 3.9 </Td> </Tr> <Tr> <Td_colspan="8"> When two ghosts from Leo's past return to seek revenge, Leo faces his demons by submitting, causing Piper's life to be threatened, and leaving Paige to deal with the situation . Meanwhile, Cole tries to convince Phoebe they need a home of their own . </Td> </Tr> <Tr> <Th> 84 </Th> <Td> 18 </Td> <Td> "Bite Me" </Td> <Td> John T. Kretchmer </Td> <Td> Curtis Kheel </Td> <Td> April 18, 2002 (2002 - 04 - 18) </Td> <Td> 4301084 </Td> <Td> 3.6 </Td> </Tr>

When do the sisters find out cole is the source