Kevin is forced to work on Sunday because he has to do all the work at the garage. Shirley plans a surprise party for Curly to celebrate their year together but he is too busy revising to notice. Tom Casey introduces Kevin to his son Mark, the new mechanic. Arthur Dabner calls off his date with Emily to take Barbara out to Heaton Park where he bumps into Percy. Percy decides not to tell Emily. Shirley throws the party and Mark, who has quickly obtained an invitation, takes his girlfriend Sharon Priestley there to show her off. Kevin doesn't like working with the boss's son. Curly isn't amused by the surprise party as he has an exam in the morning. Shirley tells him she did it for him but he throws everyone out of the flat.