The CSI Vegas Season 3 Episode 10 series finale opens with Max being pulled away by bad guys. Chris is still on the ground, unconscious and poisoned.

Beau discovers that Chris is down from a nerve agent. Catherine, Josh, and Chavez are trying to find out where Max went. Josh uses dust to find a secret entrance.

Catherine and Chavez won't let Josh go through the door set with live charges to find Max. She's underground, being held hostage by Tahir. She has contact exposure to the nerve agent.

She drops a medicine syringe on the ground that treats the nerve agent. Tahir doses her with the antidote and forces her further into the tunnels.

Allie divides up the teams to get answers. Beau and Catherine check the live explosive charge on the door while Josh and Allie investigate the tunnels. At the hospital, Penny collects evidence from Chris to find out what's wrong with him.

Tahir has created a new lab underground and he's expecting Max to fix the code he's hidden in DNA.

Josh finds a way to track Max through footprints, and he and Allie continue to follow them.

At the lab, Beau and Catherine find a way to disarm the final live bomb.

Josh and Allie find a pickup truck hidden in the tunnels. In the bed of the truck, they find the dead body of Truman Thomas, their only suspect for who has Max.

Catherine thinks that Truman was tortured for information before he died. They also identified the extra blood on the truck as Valerie.

Tahir reveals that he knows intimate details about Max as she tries to stall with her tests. He reveals that Max has a new boyfriend that no one else knows.

Josh and Allie continue to process the truck crime scene and decide to follow the footprints. An uneven walk is the only thing they know about their suspect.

Penny identifies the nerve gas they're dealing with, and Sonya presents Penny with a hair Cathrine found on Truman's body.

Beau and Catherine test explosives to identify the real blast cap in the bomb.

Penny tests the hair sample. Josh and Allie find Max's vest and the bunker where Max was.

Beau and Catherine realize the explosives were military grade, not from the US.

Allie finds an Arabic gum wrapper. The test results from Penny said that the killer was from Saudi Arabia.

Catherine and Chavez realize they're up against foreign intelligence, not artificial intelligence.

Josh and Allie realize that Truman's lab was robbed, and Max worked with the stolen equipment in the lab.

Chavez tells Beau and Catherine that Saudi Arabia is responsible for poisoning Chris and kidnapped Max. Because Max was investigating the robotics lab.

They connect all the different events involving the robots to Saudi Arabia. They realize the robot allows them to be listened to as they talk.

Tahir still has Max and brags about spying with the robots. He's moved her to a new lab and wants her to finish her work.

Penny finds a camera in the robot. She explains the situation to Josh, Allie, and Chavez. Catherine and Beau give a way to narrow where Max might be.

Tahir gets ready to shoot Max but she's injected a coded message into her body. She claims it has the names of her captor and all his co-conspirators.

As she tries to run, Josh notices the bad guy with an odd gait. He follows him as he grabs Max. Tahir points the gun at Chris, and a shot fires. Tahir drops to the ground as Chavez shoots him.

At the hospital, Penny proposes to Jack while Chris is still unconscious. They finally decide to set a date. Chris wakes up.

Max and Josh box up the robot Ocho. She gives Josh back his CSI id, which reinstates him to his former position.

The series ends with Josh and Allie walking off together as Chavez watches sadly from a distance.