A bomb is discovered in a movie theater and one of the movie attendants is murdered. Most of the phones in the theater where the bomb was found received a text message associated with the bomb.

A flashback of Avery's reveals that she has seen the symbol the hackers are using on the computer of one of her ex-employees named Tobin. 

As the team tries to solve the case, they continue to run into dead ends. Avery goes to Tobin for help in solving the case. Despite Tobin's help the code commanding the bomb is the most sophisticated Nelson and Krumitz have ever seen.

While Avery and Nelson are visiting Tobin he has a serious asthma attack. Avery gives Tobin library access and he gives Avery the password she needs. 

The team tracks down the criminal and Elijah is forced to shoot him or risk being killed by a bomb. 

The team figures out that the bomb is at a mobile event and discovers the bomb on stage. Elijah and Krumitz take the bomb away from the concert and manage to disable it. 

Avery says goodbye to Tobin after he is caught trying to sneak code onto a computer in the prison.