This weeks episode was the first one where West & Chen were riding without a training officer. But their first day didn't go as they had been told it would.
In the most recent episode, Noland & Harper were called to a bank robbery in progress, After Noland got close enough to see all the action happening inside the bank. Seeing an opportunity to defuse the situation and get the hostages freed, Noland enters the building and starts to try and bring the conflict to an end.
With only the gunman, Noland and the banks' security officer left Noland. The officer shot the bank robber after he was unwilling to lower his gun. After the shooting, Noland when to pick up his weapon only to discover it was empty. This starts an investigation of why someone would try and rob a bank with a gun not loaded with bullets.
Also, in this episode, Lopez struggled to find a wedding dress that she likes that will also hide her baby bump, so she decides to call in the help of Tim. This leads to him becoming his Man of Honor and is now involved with planning the wedding.
And during West and Chen's first day, they had to keep ice cream from melting as it could be substantial evidence and were called to break up a fight that had started in the same bridal shop that Lopez and Tim were in. With them becoming P2's, both West and Chen's parents had planned a special evening to celebrate or that least that's what Chen thought. But when only her mother comes over, she knew something was up. During the evening, Chen's mother asked when she was going to get a proper job. They had allowed her to train and become an officer, but now she had done that, they thought she would do something else.
This lead nicely to officer west giving Chen a patron saint necklace similar to the one he got from this parents was a show of appreciation.