Time to meet the parents! Or, at least, it's time to have the parents meet. Okay, Martha Rodgers and Jim Beckett met awhile ago, but they've never really socialized. That's why Castle and Beckett set up a dinner with his mom and her dad. Worlds collide! Jim doesn't think much of flakey actors and Martha doesn't care for his love of boring baseball. These two have nothing in common. Castle and Beckett are caught in the middle of a total train wreck of an evening. Thankfully, there's been a murder!
Father Joe McMurtry is gunned down in cold blood in an abandoned building. A local bar owner says a customer named Leo was mouthing off about how he saw someone fleeing a building after gunshots were heard. Ryan is a little uneasy about interviewing a nun. Being a homicide detective is a cakewalk compared to the combat he faced back in Catholic school. The good sister believes a mob enforcer named Mickey Dolan killed the good father. These two polar opposite adults were best friend as kids. Father McMurtry spent a lot of time trying to save his old pal's soul.
Castle and Beckett are caught off guard when Mickey Dolan's men sneak up on them at the home of Leo the witness. They lock themselves inside the apartment after the mob thugs snatch up their phones and Beckett's badge and gun. They hit the streets with Leo to find that Beckett's car has been stolen. They are stranded in a bad Bronx neighborhood where no one opens their door at night. Beckett breaks into a car to swipe a cell phone. Too bad it's password-protected and the car alarm gives away their location to the bad guys. Better hide!
Castle wants to figure out the cell phone's code. Beckett wants to make a break for the subway. A nervous Leo thinks he's going to die while in the care of this bickering pair. All squabbling ceases thanks to Carly Rae Jepsen. Her ringtone allows Castle to answer a call from the phone's owner, who is too ticked at the thief who swiped her cell to sympathize with his plight. That's cool. Castle deduces that her password is her cat's name: Lola. Unfortunately, the kitty-loving caller remotely disables her phone before he can dial up some help.
Captain Gates learns from Esposito that there was a struggle at Leo's place. She lets a worried Martha and Jim know that they've temporarily lost contact with their kids. Speaking of the parents, they call a cease fire while sympathizing about how much they worry about their children. Fortunately, Castle and Beckett always have each other's back. In other news, the team learns that Father McMurtry was trying to get Mickey Dolan to turn state's evidence against the powerful O'Reilly crime family. The feds lost the enforcer once the mad mob man heard his priest pal had been killed. Dolan is out there looking for revenge.
Leo the witness twists his ankle as the defenseless trio tries to catch a passing cab. They duck into an open cellar to avoid pursuing mob men. Leo's ankle is bad. Castle convinces Beckett to stay with him while he goes for help. They have a heart-to-heart chat about the “different worlds” thing that's afflicting their parents before he leaves. Leo then lets Beckett know that living life in the now makes a lot more sense than worrying about the future. As for Castle, his future is in jeopardy once he's snatched up by Mickey Dolan.
Castle does his best to avoid Mickey's questions as to where Beckett and Leo are hiding, but the mob enforcer is pretty good at reading bluffs. A thug breaks into the cellar. Amazingly, Leo takes him out with ease. Beckett realizes this guy isn't a witness. Leo is the killer! He's been running a ruse to get Mickey Dolan to come to him so he could assassinate him for the O'Reilly crime family. His plan seems to be working. Leo has his hostage call Dolan, who hands the phone over to Castle. Beckett says how nice it would be to take their parents out to something all four of them would enjoy, like a baseball game, if they survive the night.
A meeting is set up under a borough bridge. Beckett is horrified when Leo opens fire on Dolan's car. She rushes over to look for Castle, but he's not inside. No one is. Castle knew something was up when Beckett implied that his mother would enjoy baseball. He convinces Mickey to spare Leo's life because that's what his old priest friend would want him to do. As for Castle and Beckett, they are shocked to see their parents are getting along swimmingly back at the precinct. Guess people from different worlds really do have a shot at making things stick.