On Beauty and the Beast Season 3 Episode 10, Cat and Vincent work together to try to track down Liam. Cat wants to look at the case as a police case, but Vincent wants to track down Liam the beast way. The couple decides to compromise and Vincent goes to track down Liam. He's able to track him down the Alton's hospital room, but is too late because Liam has already set off a bomb in the hospital killing Alton and other patients.
The notion that Liam is still after the people who have had serum in their blood makes Tess realize she needs to move JT right away. She ends up taking JT to safe house and they try to wait things out. Cat does some digging into Julianna's files and finds a case about Patient X which turns out to be Julianna's brother Russell. Russell is starting to have side effects of the serum and it's slowly killing him, but he is able to provide Cat and Vincent with information on Liam. He tells them Julianna didn't willingly inject Liam with the serum and was actually tricked by Liam.
Cat takes Russell to the police station after another bomb Liam set goes off almost killing Russell. At the station, Russell has a meltdown, takes Cat's gun and is determined to set a trap for Liam by using him as bait. Russell goes to where JT and Tess are and Liam is hot on their trail. Cat and Vincent show up just as Liam kills Russell, sets yet another bomb, and goes after JT. Vincent gets into a fight with Liam and it's revealed Liam is actually an enhanced beast which makes him even harder to kill.
In the end, Liam is able to get away. JT realizes he is having the same symptoms as Russell had which makes him believe the serum is slowly killing him.
Don't feel bad if you missed out. You can watch Beauty and the Beast online now via TV Fanatic and catch up on the entire season.