Episode406, "Day In The Life"
SEASON 2, EPISODE 209 - A young couple kidnaps back their own baby a month after the young mother gave the child up for adoption. The unstable bio-dad has just reentered the mother's life, and convinced her that she needs to get the baby back at all costs, so they can become "the perfect family". The couple unexpectedly shows up at the adoptive parents door. The adoptive father becomes annoyed. The biological father soon becomes violent with the adoptive one. Then the couple kidnaps the baby and flees in the victim's vehicle. The SRU team is called in to track down the perfect family, and stop the unstable father from harming the baby, his wife or himself.