On 29 December 2019 through to 5 January 2020, 3 episode Specials aired on CBBC and BBC iPlayer titled 'Flashbacks' which saw past and present cast members react to their favourite and funniest moments from the show.
[5] 13-year-old Josh Carter (Khalil Madovi) is shocked and annoyed to discover that his older brother Nathan (Doc Brown) is the new English teacher and detention monitor at his school, Elmsbury High.
Josh, Ryan and Ash sign up for the school football team to get out of lessons, but discover that even studying is preferable to PE teacher Thorne's strict disciplinary regime.
Bell initiates a big clamp-down on security and truancy in school, meaning there are no more visits to the ice cream van just outside the front gates.
When Dexter enforces the no-phones rule in the 4 O'Clock Club, Josh rebels and decides to test once and for all just who is in charge in detentions – the teachers or the pupils.
Trouble arises on the day of Nathan and Mel's wedding as Josh squabbles with his younger cousin Nero, Zoe-Marie, Molly, and Agness are bridesmaids, and Dexter, Ash, and Ryan are in charge of organizing the school auditorium for the reception.
After Elmsbury burns down after the wedding, the gang (save for Ryan and Molly) arrive at their new school Fowlmere Manor, where they meet new faces.
Meanwhile, Nero wreaks havoc – at Josh's expense, while Dexter tries to impress his new colleagues with a first aid demonstration and nearly scares his new pupils to death.
Note: First appearance of Mr Graham Nunn, Isaac Rodgers, Eli Grant, Owen Garland, Fleur Murphy, Eleesha Rahaad, Miss Emma Parkwood and Mrs Aine O'Brien.
When Josh plans to audition for a spot at Hillview Institute, a music academy, his dream is thwarted when he discovers that he needs a perfect academic record.
To add more disappointment to the situation, Nero discovers his parents are unable to attend the musical, so, tired of being let down by them continuously, he runs away with Clem from Elmsmere to try to find them in Kuwait.
Meanwhile, Isaac discovers that Bell is the mystery "phantom sprayer" who has been graffiting insults about Andress all over Elmsmere (a running gag throughout the fourth series).
Note: Agness Addo, Zoe Marie Ingham, Ashley 'Ash' Newman, Nathan and Josh Carter guest appears in this episode.
He arrives to update his friends, but makes matters worse by quarreling with Clem after she accuses him of succumbing to adult tyranny (contradictorily, she has a slight crush on him).
When Mr Nunn is sent to hospital following a crash, Lizzie offers to do the camping trip which means Dexter must take Nero to the hot tub hotel.
When Clem, Eleesha and Fleur accidentally knock a metal fence onto it, the flower gets crushed - but they blame Nunn so they don't get into trouble for it.
Meanwhile, Dexter and Lizzie are expecting a baby but Mr Nunn isn't happy when he has to cover their lessons whilst they go to an antenatal class.
The following day, she phones Mr Bell and asks to come and see him in action, unaware that the book was written many years ago and he is in fact no longer a head teacher.
CJ decides to act cool and admit he did it to Amber, Violet and Darnesh but Mr Nunn overhears and takes him to the head's office.
It is later revealed that Mr Bell had planned to marry his now ex-girlfriend Anastasia but he has to cancel the wedding in an attempt to get his money back for a deposit on a new flat for him and CJ.
At the stag-do, Mr Nunn makes the boys dress up as superheroes but they end up getting arrested after Dexter gets handcuffed to a chair at the restaurant.
Amber, Darnesh and Violet try to convince Ingrid that Mummies are real but they scare Mr Nunn by accident who breaks museum property - he is arrested.
Mrs Goodman decides to return to her position as headteacher and cancels the talent show, much to the distress of Mr Bell who has to deal with the repercussions.
New music teacher, Clinton Russell, is late for his first day at Elmsmere after his girlfriend, PC Emily Rose, has to tend to a call out.
Meanwhile, Chester, Issac, and Darnesh are the school's new fire safety officers, however, their test runs of the new emergency facilities annoy Bell.
Bell orders Clinton to prepare his presentation, but after a seagull poops on him, he sits in the police car where he finds Emily's niece and nephew.
Mr Bell is trying to practice his magic trick but it goes wrong when he accidentally swallows the key and can't set himself free.
He gives her a set of keys that she promises to keep safe but after leaving them on her desk in the office, Reiss takes his chance to steal them so he can get his centipede back.
Fleur, Eleesha, Polly, Evan, and Katie are unhappy with the dress code for the sixth form so they protest by wearing costumes from the drama department.
Note: Last appearances of Mr Clinton Rusell, Owen Garland, Chester Garland, Fleur Murphy, Eleesha Rahad, Katie Turnbull, Polly Morgan, Evan Lloyd, Isaac Rodgers, PC Emily Rowe, Mr Graham Nunn, Amber Baker, Violet, Darnesh Palmer, Ingrid Ingham, Mrs Morgan, Reiss, Coco, Henry Ford, Magnus, Miss Susan Wrigley and Crispin Bell.