Fergus is upset that there are no baby pictures of him and storms of to the attic. He goes through the mirror. Mandy finds a picture of Fergus as a baby and puts it in the frame of the mirror where Fergus is sure to see, however he never sees it as he becomes the baby Fergus. Constance tells Daniel and Mandy that her mom had found him and they plan to get him back. Back in present time the gang need to find the most recent picture of Fergus. The decide the picture that Their mom took that morning is the most recent. Returning through the mirror Fegus is clueless of what happened, to his self. (thetvdb.com)