A bank manager is retiring and the team is having a small party for him. When the timer goes off for the bank drop, things go as planned, until the courier collapses and starts foaming at the mouth. As does the bank manager who is still in the fault. 

The first responders arrive and when the vault starts to close, Hen runs in to tend to the manager and is locked inside. Soon thereafter she collapses. 

The power is cute to the bank so the firefighters van drill a hole into the vault and get air in. Afterward, they manage to pull out some of the concrete wall to get into the vault, just as the doors open. 

Shortly after they return to the firehouse, the police show up and find $300,000 in the fire truck. 

The police interrogate everyone but are unable to nab a suspect. 

Athena and Hen return to the bank and start searching the vault. They find the bank managers hand sanitizer and believe that the toxins that caused Hen to collapse were inside of it. When they go to confront the manager, they find him dead. 

The cops serve everyone who was at the bank search warrants. 

The toxicology report comes back and shows that Hen had scorpion venom in her system. She then realizes that the robber was Marty, the man who fixes the fire trucks. He, along with his ex brother in law (the bank manager), concocted the plan to steal the money. The bank manager also stole diamonds during the time the power was down, and swallowed them so they coouldn't be found. He would later die due to the intestinal blockage. 

The Chief comes to Bobby and tells him that he is on leave, as the LAFD discovered new information from Bobby's past while the team was being investigated.