Title this, if things can go wrong, they will.
Andy and Sam get ready for their wedding day. A guy who says he's Sam's dad shows up at the precinct. Says he's driving with Dov and Chris to the church.
Andy tries on her dress. There's a knock on the door. It's Nick. He can't come to the wedding. Meanwhile, Andy bends over and rips her dress. Nick says he'll sew it on her. Nick leaves and Andy finds out her ride is going to be late. She decides to drive herself, taking Sam's truck.
Meanwhile, Traci is supposed to be helping with the wedding, but is stuck at the office on a murder case. Wife is found at the bottom of the basement stairs, a hammer having smashed her head. The husband says they had a happy marriage. But don't all husbands say that?
Sam's dad says he has to make a pit-stop on the way. Meanwhile, Andy is getting lost. She goes by a car with a seemingly unconscious driver and doesn't even notice. Shortly after, she picks up a young woman who says she is desperate for a ride. Her name is Starr and she's very anxious. She says she ran into a creepy driver before Sam. He was in the car that Andy passed earlier. Andy starts to ask Starr questions and Starr tries to get out of the truck. Andy goes back to the passed car to confront the driver. When she gets out of the truck, Starr steals it and drives off. Meanwhile, Andy discovers Starr stabbed the driver.
Sam makes it to the church. No Andy yet. Meanwhile Dov asks a colleague to run a check on the pit-stop that Sam's dad made. It was the house of a known convict. Sam's dad says he had to get a watch that was in there, that used to belong to Sam and that he needs to give back to him.
Andy calls Duncan, but her phone line goes dead. The stabbed driver says Starr stabbed him, robbed him and took his car keys. Andy works to keep the driver alive, asking him to tell her what he had planned to do that day. His name is Angus. He was on his way to surprise his girlfriend. Andy realizes she needs to get help fast and Angus can't move. She runs to the highway to get help.
Traci's team realizes the murder case is not a case at all. The wife was using the hammer to separate a frozen chicken. She tripped on the stairs when taking the hammer back to the basement.
Meanwhile Sam's dad makes it to the church. Sam is not happy to see him. His father is an ex-con. He gives Sam a hard time about Andy not being there, says at least his wife showed up for his wedding. It's clear that he was tough to live with, when he wasn't in prison.
Traci finally makes it to the wedding. But still no Andy. Meanwhile Duncan finds Andy. They rush back to Angus. Sirens can be heard. Help is on the way.
Meanwhile, back at the church, the wedding party has to clear out for a funeral. Andy is finally able to reach Sam. She assures him that she's coming. The wedding is on.
Sam says his vows, telling Andy that she took a broken man and made him whole. Andy tells Sam that she has loved him from the moment she met him. They exchange rings and are now husband and wife.
It's the next morning. A new group of rookies are starting. It all begins again.