Erin and Anthony get in an argument when Erin tells Anthony not to use the office for personal business and he fells she lets her family do it. He storms into his office, where a witness calls him just before getting shot.
Jamie and Eddie find an abandoned baby.
Danny and Baez are called to the scene of the murder and find out that the victim's last call was to Anthony.
Sean comes to see Frank. He had to take a DNA test for a school project. He thinks he has a cousin he's never met.
Erin and Anthony explain to Danny about the witness. Without him they have no case.
A woman comes to see Frank. Her son is a cop. He is Joe's son. She never told Joe about him. She wants him transferred to a safer assignment.
Eddie talks to a doctor who says the baby will be okay but is unlucky because he was abandoned and left to die.
Jamie tells Eddie that the detectives are looking for the mother. Eddie wants to help find the mother. Jamie doesn't think this is a good idea.
Danny and Baez talk to a friend of Gio's who says Gio was with his girlfriend who he was fighting with. He can't believe Gio is gone.
Sid has looked into this relative. His name is Joe Hill. Frank wants a meeting with him. Sid gives Abigail a look as he leaves. Abigail stays behind. Frank tells her that Hill is is his grandson. He doesn't think Hill knows.
Erin and Anthony question Acosta. He is uncooperative and sneers at them.
Joe Hill comes to see Frank. They have an awkward conversation. Joe wonders if he is in trouble. Frank tells him he's just checking in to see how things are going in his unit.
Danny and Baez try to talk to Gio's girlfriend. She says Acosta owns the neighborhood and cooperating with the cops is stupid. She says she was going to marry Gio and storms off.
Eddie is determined to find the mother. Jamie offers his help.
Security footage shows Gio's girlfriend took photos of what was on his phone.
Jamie and Eddie talk to a store clerk who is distracted by having a crush on Jamie. She did see a pregnant woman but can't describe her.
There is a family meeting. No one knows what it's about. Frank comes in and tells them about Joe's son. Everyone is shocked. Danny thinks it's a scam but Sean says the DNA test is accurate. They talk about how Joe is like the rest of the Reagans. Sean thinks they should invite him to Sunday dinner. Frank isn't sure but Henry thinks it's a good idea and so does everyone else.
Jamie fills Eddie in. He is worried that Frank will get hurt. Eddie somehow relates this to the baby. How could the mother leave him? Jamie thinks she left him in front of the precinct for a reason. Eddie says if she loved him she would make sure he had a good home. Also she named him Cayden.
Tech has found the photos. They're of texts between Gio and the DA's office. The girlfriend sent them to Acosta.
Erin's judge refuses to delay the proceedings.
Jamie and Eddie catch up with the mother. Eddie freaks her out by yelling at her. The mother sobs and asks if the baby is okay.
The girlfriend is brought in for questioning. She denies everything. Danny has a photo of the texts. She says that Acosta would have killed her if Gio testified. Danny threatens to make Acosta think she is cooperating with the cops if she doesn't talk. She tells him Cortez is the shooter and Acosta may have him killed soon.
Ms. Hill says she didn't want her son to live in the Reagan family's shadow but now she told him. She wants her son reassigned still. Frank says he always wondered if he should have put Joe in a safer unit. Frank says cops are in danger all the time. He is trying to think of what's best for Joe. She says don't contact them until he decides to reassign her son.
Danny and Bae arrive and find Teddy holding Cortez hostage. He wants to get revenge for Cortez killing Gio. Danny tells him somebody killed his brother too. And Baez's too.He convinces Teddy to drop the gun and Teddy and Cortez are both arrested.
Erin tells Anthony the judge will let her read Gio's testimony and Danny might have something. She hands Anthony a letter. It is the information he wanted. She wanted to show him he's family too.
Jamie tells Eddie that the mother was the victim of a baby selling ring who wanted to pay her $2,000 to give up the baby. Eddie is upset that the mom will get him back. She says she's happy he's with his mom but she can't think of a reason why they found him. Jamie says the reason is they saved his life. Jamie says he knows how they can get a baby that's theirs.
Erin wants an adjournment. She tells the judge they have evidence that Acosta killed Gio. This time the judge grants her motion and Acosta is arrested for Gio's murder.
Sunday dinner. Sean is late. He comes back with Joe. They all introduce themselves.