First of a dramatic two-part episode which began the 18th series of Casualty. A packed train is derailed to the thunderous sound of screeching brakes and breaking glass. In the chaos that ensues, a multitude of casualties are tended to by the arriving team who are shocked by the catastrophe.

After losing her legs in the train crash, Anna dies after spending her last few moments alive with her friends and the love of her life Merlin.

As the three doctors are pulled from the cave, Lara forces Harry to consider the consequence of his actions. Simon fights for his life, Jim comes to realise the truth about Nikki and Charlie races off to stop his son being taken away to Canada by his stepdad.

Roxy and Nikki have a big fight resulting in Nikki threatening to leave the home but her mind is changed when Roxy goes into labour in the car, giving birth to a little boy who has trouble breathing. Tally is extremely jealous of Simon and Lara so she throws a brick through Simon's window when she knows Lara's there; she also defaces Lara's car. Contributor: DouMarNutBle

Luke and Josh find themselves being held at gunpoint by a man who demands drugs from the ambulance. There was a struggle in the back of the ambulance and a gunshot was fired. It turned out that the gun had gone off and the man, Greg dies leaving Luke feeling guilty when he finds out he has a family. Roxy continues to spend all her time at the hospital with William. Tally hides important about a patient from Lara putting the patients life at risk. When Lara questions Tally, Tally says Lara deserved it for stealing Simon away from her. Later on Simon tells Lara he loves her.

Harry has to suspend his daughter when she confesses to her crimes against Lara and it's a bad day for Simon as Lara finds a bag of coke in his pocket and after he tells Tally she was the biggest mistake of his life She commits suicide in the hospital toilets and the doctors have to resuscitate her but will she survive? Roxy says a final goodbye to her baby as the surrogate parents take him away and Josh has to suspend Luke following the investigation.

A prison riot forces Harry to shut down most of the department to make way for injured prisoners. One of the prisoners takes Roxy hostage to escape but she is rescued. Harry continues to blame Lara for Tally's condition and things get worse for Lara when Simon turns up at the hospital high on drugs. Meanwhile Abs tells a reporter more than he should have.

Abs faces it tough this week when a young child he is caring for dies and the psychiatric nurse faces the father wrath leaving Abs lying in a pool of blood.

Lara discovers how bad boyfriend Simon's drug problem is this week when she finds him taking speed at work. When Simon goes home Lara predicts the worse and drags Abs in to help her but when they arrive at Simon's he is completely drugged up and Lara is forced to tell Abs she needs help to help Simon. Also Jim annoys his colleagues by trying to enforce new rules which he used in America and Luke and Bex go out for a drink.

Jim becomes an unpopular man this week when in Harry's absence the now in charge paediatrician makes a number of changes which start to anger a number of his colleagues. Things get worse for Jim when a patient dies in reception and Jim is blamed because of his new rules. The engagement ring Fin lost at the train site has been found - will this pro-mt Fin to finally propose to Comfort and Simon finally confesses about his drug addiction to Lara.

Lara, Nikki and Josh find themselves taken hostage when they are called to a scene which they enter only to find that a couple of bank robbers need help. As the two armed robbers do a runner they take Nikki and Lara with them as hostages. After driving off in the ambulance, Nikki and Lara are tied up in the back before they stop at a bridge. With the police catching up to them one of the robbers takes one of the hostages out of the ambulance to show they will shoot. However it takes an unexpected twist when the hostage is pushed off the bridge. But who is it Nikki or Lara and will they survive?

Nikki is rushed to hospital as it is reveled she was the one who was pushed off the bridge but will she survive? After a high speed car chase the two robbers are arrested and Lara is brought to safety.

Things go from bad to worse for Nikki, still dealing with the trauma of being held hostage, the young paramedic finds out the right side of her body is paralyzed and Lara begins to blame herself for Nikki's condition.

Comfort & Fin finally say 'I Do' in a beautiful ceremony. Meanwhile Nikki decides that it's time to move on & no longer able to be a paramedic she decides to see a bit of the world and says her goodbyes.

New technician Nina Farr arrives on the job but riles Comfort up the wrong way straight away. Things take a worse turn when she's called to a shout - not knowing that it's her boss Josh whose ceiling has caved in after leaving the bath on - and treats Josh with little respect. Will Nina be able to get past her terrible first day? Meanwhile Josh's date with Caroline doesn't go as planned and Lara takes desperate measures to make sure Harry doesn't accept Simon's resignation.

Nina continues to cause problems for the other paramedics as she ignores Fin's instructions and climbs down a sewer to save a man who is trapped but the oxygen starts to run out and Nina's life is also in danger. Luckily. Nina and the man manage to survive but Nina ends up in trouble with Josh for disobeying Fin's orders. Meanwhile, Simon is summoned to see Harry, knowing too well that his job is on the line. Josh is heartbroken when Caroline decides not to go on another date with him and Bex continues to plot to get Luke back. Contributor: Adam Hague

Josh and Nina have to put their differences aside when they have to rescue Jim's daughter's puppy. Simon and Lara set a date for their wedding but after a stressed out date, Simon turns to drugs once again. Will his marriage to Lara be over before they've even walked down the aisle? Contributor: Adam Hague

Lara and Simon enjoy their last night of freedom tonight but Simon becomes angry when Lara and her girls turn up at his venue. Convinced she is here to check up on him Simon walks out only to be caught taking drugs by Abs. When confronted Simon storms off and heads to the home of another woman. Will Simon cheat on Lara? Meanwhile Tess faces a tough day when she tries to find out how a beaten woman came to get her injuries. Bex tries to get back together with Luke but he ends up going off and kissing Bex's best mate Claire while Abs and Nina look like they're finally going to get together.

It was the day of the wedding. Abs arrived at Simon's house only to catch him with the woman he met last week. Abs was outraged but a defensive Simon threw him out. Simon asked Jim to be best man. Bex overheard Luke and Claire discussing their kiss last week. A distraught Bex slapped Claire. Abs rushed to the wedding to tell Lara about Simon's infidelties. While Jim was flying Simon to the venue, a distraught Lara phoned Simon to call off the wedding. In frustration, Simon took out a packet of pills which he dropped under Jim's seat. As he struggled to get them, Jim lost control of the plane. They crashed and although Jim managed to escape, Simon was caught in the explosion. When the others saw the smoke, they rushed to the crash. They fought to save Simon but were they too late? Meanwhile, Lara fled the wedding with Harry. Oblivious to the crash, she instructed him to take her to the airport. She called ahead and bought a one way ticket to Australia.