Fallen

This first episode of the new season picks up where the last season left off, with Horatio Caine racing back to the CSI offices after receiving a tip-off note from suspected serial killer Bob Starling. Suspecting the worst, Horatio arrives to find his team collapsed on the floor - they've been gassed! Shooting out the windows allows in fresh air and the CSIs start to recover, but Jesse, who's hit his head on passing out and has died as a result.

Stunned and mourning the loss of their colleague, the team are determined to avenge Jesse's death but all the evidence against Starling has been contaminated by the gas or by the actions of the emergency personnel. They need new evidence and Natalia tries Starling's PhD student, Melissa Walls, but she claims to be too busy to help...

The tanks that fed halon gas into the office air con system have come from Starling's university and must have been set off by an accomplice - but who? Horatio and Eric visit Melissa but find she's been tied up, with a gun rigged to shoot her if her door opens. Horatio releases her and soon discovers the gun belongs to the university janitor, Keith Garwood. He, however, pleads ignorance.

Then Horatio discovers a hidden message in Starling’s note, suggesting a bomb has been planted at a seaside pier. It’s only a distraction, however, and while Tripp is transporting Starling to prison, his car is halted by gunfire and Starling gets away.

Meanwhile, Walter and Benton recover deleted photos from Starling’s camera, including intimate shots of the killer and Melissa – she’s his accomplice! She’s quickly arrested and agrees to cut a deal to avoid the death penalty.

Melissa meets with Starling at his yacht and, wearing a wire, gets him to admit to everything he’s done, all the team need to convict the killer of Jesse’s murder.