Next week on Casualty, Sah's backstory is explored and Ollie's ordeal prompts David to make a big decision.

Here's a full collection of the biggest moments coming up:

1. Sah visits their dad

Sah unwraps their birthday presents with their dad, Kevin.

Kevin asks if they're celebrating with the other paramedics, but Sah dodges the question. Sah also gets a card from their mum in the post but rips it up.

Kevin mentions that his carer isn't coming that day but insists Sah doesn't have to stay at home with him.

2. Iain gives Sah some advice

Iain tells Sah that they need to be more empathetic to the patients they bring in and Sah promises to do better.

Sah and Iain arrive to help injured Willow home ? who has been burned by the acetic acid used to develop photos.

Sah tries a lot harder to empathise this time, something which is noticed by Iain.

3. Ollie's bullying ordeal continues

Ollie is humiliated in front of his entire school, as his bullying ordeal continues.

Witnessing Ollie's anguish, his friend Rob promises to get even and trashes bully Dan's car.

This momentarily lifts Ollie's mood but the situation comes back to bite them when they are chased by a police officer. They try to run, but Rob falls and injures his leg.

4. Sah gets a blast from the past

Sah and Iain respond to a call in a carpark and it's clear Sah recognises the patient ? Scott.

There's clear animosity between them, and Scott doesn't hide his confusion about how Sah has come to be a paramedic given everything that has happened in the past.

5. Ollie is brought back into the ED

David is furious to find Ollie at the ED with the police officer and berates his son for showing him up at work yet again.

Unable to get anywhere with Ollie, David speaks to Rob instead.

When David admits that he doesn't really understand what his son is going through, Rob tells him that Ollie misses Rosa.

6. David reaches out to Rosa

David struggles to understand why Ollie's been acting out recently, and feels shut out.

Following his conversation with Rob, David tells Faith that Ollie blames him for Rosa leaving.

Later, David attempts to reach out to Rosa, but what will happen when he does?

7. Sah's past is revealed

As Sah is called back out to treat their dad ? who has injured himself while home alone ? Scott tells Dylan about their shared history.

When Dylan notices Scott's previous injuries, Scott tells him that Sah used to beat him up when they were younger.

After Sah has an explosive showdown with Scott, they tell Iain the truth ? Scott bullied them in school about their dad's disability.

Sah explains that, because of this, they would lash out and that's how Scott got his injuries. Iain supports Sah, but will Dylan be so understanding?

Casualty airs these scenes on Saturday, May 7 on BBC One.