Peter is woken in the middle of the night by someone abandoning a new born baby and he calls in Dr. Ryan to examine it. Assumpta, walking Finn, spots the doctor's car outside Peter's house and she knocks, worried that he has been taken ill. She discovers the baby and, discovering her maternal instinct, she offers to help with the baby. They spend all night playing mummies and daddies, a fact that they decide to keep quiet about. The baby is taken into hospital and Peter sets about finding his mother. Meanwhile, tragedy strikes for Niamh and Ambrose when Niamh loses the baby. She turns to Assumpta for comfort, Assumpta then is left to break the news to everyone else. The baby and his mother are reunited and Peter gives his talk on family planning. Assumpta is pleased when Peter reveals that he has finally got one over on Fr. Mac.