S4·E20 Butterfly's Wings

Dave and Julie discover how one inexplicable chain of events can almost end in disaster. Dave is alone with Ruby when he gets a call requiring his presence back on site. With no babysitter, Dave takes Ruby with him and enlists Coby to look after her. For a brief moment Coby takes his eyes off Ruby and she wanders into the building site. Panic sets in when Dave discovers she's locked herself in a room with a dangerous drop. Will they get to her before it's too late? Meanwhile, Ben is doing his best to take things slowly with Emma, but Carbo makes his disapproval known after having witnessed Ben and Emma's kiss.