"Back to School" is the 1022nd episode of Casualty and the 18th episode of the 31st series. It was preceded by "What Lurks in the Heart" and followed by "Little Sister". The episode was directed by Jamie Annett and written by Laura Poliakoff.
At the start of an early morning shift, the GMC visit the department after Connie's allegation against Elle. Jacob later questions Connie on why she had to go to the Trust, but she made it clear to him that she wasn't intending on backing down. Meanwhile, Cal brings the cufflink into work and suspects that Max is seeing Alicia.
Elsewhere in Holby at an illegal rave, the police arrive; amongst them is Sergeant Ray Thompson and PC Jessie Nichols. As soon as they arrive, worried teens flee towards the exits. Ray confiscates some drugs from a man, but later gets a can thrown at his head by another man named Nate. He chases him throughout the club and when he eventually catches him, Ray hits him several times with a baton, and throws him against a metal pillar. In an attempt to escape, Nate scales some scaffold where Ray follows behind. However, the scaffolding collapses, leaving Ray with a trapped arm and Nate impaled through the leg with a metal bar. Jessie and a woman named Rhian watch on helplessly, and call for an ambulance.
Meanwhile, David struggles to connect with Ollie despite putting in effort to make sure he's keeping him happy. When David arrives at work, he's surprised to see that Ollie's school teacher Tim has been admitted. Dylan examines the nasty rashes on his body which are bleeding from where he's itched them so much. During this time, it also transpires that David running off to Acupulco is the news of the school. David's even more upset upon discovering that he didn't even know about the school play Ollie was in, despite the fact he told his teacher that David was working.
Nate and Ray arrive in the department for treatment, and whilst assessing him, Duffy and Elle notice the bruises on his legs caused by Ray. He tells them what happened, and Elle trusts Jacob to get to the bottom of what happened. Ray is adamant that Nate assaulted him and that he was only acting in self defence. Jessie stays quiet, but Jacob is convinced that she's hiding the truth. Cal speaks to Alicia and she tells him that she's not seeing anyone else. Meanwhile, Charlie is annoyed when the wedding invites are accidentally printed on black card.
Dylan and David continue treating Tim, when he finally admits to having Klinefelter's Syndrome: he has three sex chromosomes (XXY). They're initially irritated that he didn't tell them sooner, but soon realise that he only upped his dose of foreign remedy medicine because his wife was ovulating and they were trying to have a baby; his sperm count was very low but not zero. Meanwhile, Noel tries to organise the staff room to help everyone, after he grows more worried about the machines taking over his job. However, this only irritates the other staff as he's put them in the wrong place accidentally.
Elsewhere in the department, Nate is being taken up for an operation when he suddenly takes a turn for the worse. They predict that he has brain damage upon seeing the mark on his head. Duffy informs Elle when the scan comes back and she's left doubting her medical expertise. Connie doesn't help matters by rubbing in that Elle, in her eyes, is unfit to work and run the department.
Robyn accompanies David to the school play that afternoon, where Ollie tells him that the reason he didn't tell him was because he didn't think he'd want to go into the school after the rumours were spread. After the performance, David admits to Robyn that the medication he's on isn't allowing him to be the best father to Ollie, and tells her he'll be reducing his dose.
Jacob informs Jessie that Nate has brain damage, but she still doesn't speak up. It's only when Ray and Jessie are outside that she finally speaks up to him. He tries to restrain her, but Jacob is able to let her go and she tells Ray that she's going to make a statement. After the shift, Jacob tells Connie that if she doesn't retract her allegation, their relationship is over. Unwilling to do this, Connie is upset at the prospect of losing Jacob, and he agrees to go round to pick up his things.