Merger is the third episode of the third series of 4'O Clock Club.
Josh is prepared to face Fowlmere after Elmsbury burns down at Nathan and Mel's wedding. Nero is annoyed at having to move schools and had to wear Josh's old uniform. Dexter is nervous about the merger, and was asked by Mr Bell to do a first aid demonstration as an insurance practice after the fire. They arrive at their new school, and Josh conflicts with pupil Isaac as a result of sharing a locker with him as there weren't enough lockers for each pupil to have one to themselves. Nero ends up sharing with pupil Eli Grant, who he quickly becomes friends with as well as Owen Garland, and Mrs O'Brien, after catching the three play truant, thinks Nero is Josh because Josh's name is in his old jumper. He causes more mischief under Josh's identity until Josh's mum and his aunt is called in to be spoken to about Josh's behaviour. Josh is enraged upon learning he is doing home economics over music and asks Dexter to change this as he is the new head of music but after both Dexter and Bell speak to Mrs O'Brien they refuse to let him change. After Eleesha sees Dexter put a first aid dummy in his car under a blanket, she mistakes it as a dead body and tells the 4'O Clock Club who Dexter tells it was just a first aid dummy but they go and see for themselves and there's nothing there. Nero, Eli, and Owen took the first aid dummy, dressed it up as O'Brien, and put it on the drum kit. They are caught by O'Brien and Nero is sent to the office where his aunt is, with O'Brien thinking he's Josh. The real Josh takes some cakes to the office to bribe O'Brien into letting him do music but walks in on his mum. O'Brien ends up realising she has been tricked, lets Josh do music, and when Nero goes home he discovers his mum has bought him a proper uniform and he is staying at Fowlmere.
- Layton Blake who played Isaac in this episode appeared in Series 2 episode New Term however was referred to as Fowlmere Josh and was only a guest appearance.
- Elmsbury Academy pupils as well as some teachers have moved to Fowlmere Manor, to be renamed Elmsmere Manor in the following episode.
- Ryan and Molly have left the series and attend a private school off screen. Miss Andress is a teacher there.
- Nero has become a regular in the series.