Will helps Natalie pack her car. They say goodbye and he tells her to keep in touch.

Meanwhile, Archer low-key accuses Charles of being responsible for Ethan getting shot. Charles isn't having his BS and reminds him that Archer is the one who took out the shooter's appendix without permission.

New doctor Dylan Scott sees a kid who looks to be about eight who has been bitten by a snake. Scott used to be a cop and realizes the kid is wearing gang colored shoelace tips. He wants details. Finds out the kid grabbed a snake out of a box as a gang initiation. Outside, Scott tells Maggie to call his dad who is a lieutenant at CPD.

Halstead goes to Goodwin to beg for his job back since he didn't actually steal the meds. Goodwin will rehire him on one condition: she wants him to spy on Matt Cooper and find out if he is getting kickbacks for unnecessary use of a heart machine that may be causing pulmonary embolisms.

Goodwin reintroduces Halstead to the staff. Archer is standing in the background looking unhappy. Goodwin also introduces the two new doctors. Halstead already knows Hammer. Turns out they went to med school together and she always had to be number 1. (Possible new love interest?)

A patient comes in with heart failure but Marcel can't get her chart because she was a trial patient and Kender revoked access to all trial patient charts after the fiasco with the stolen meds. Archer blames Halstead for this, but luckily Halstead remembers the patient and even makes small talk with her while Marcel does an ultrasound. After, Will says this makes no sense, the patient didn't have such severe disease before the trial, etc. Marcel will order more tests to see what is going on. Archer feels a need to inform Will that he wouldn't have rehired him if it was up to him. They exchange barbs before Archer is called away.

Archer and Vanessa see a woman who refused to wear a hospital gown because her twin wasn't issued one too. Said twin wants an IV too and when Archer suggests the woman may need surgery to remove her ovary, the twin wants the surgery too because they are supposed to be identical. In the hall, Archer tells Vanessa to page Charles.

Charles interviews the twins, then tells Archer and Vanessa that while this is not normal, there is nothing they can do. They can't operate on the healthy twin and they can't operate on the unheallthy one without permission.

Scott stops Will in the hall. He knows Jay from working in PD for a while. Scott is called in to see a patient, ending that convo. It's a little girl with sickle cell anemia who is mostly unresponsive. (What happened to the little boy with the snakebite and gang affiliation?) The mother has pain too. Scott orders a head CT and a blood transfusion.

Will sees Cooper at the cafeteria and makes small talk,t hen suggests they catch up over drinks.

The sick twin takes a turn for the worse and needs emergency surgery but won't consent unless her twin has surgery too. Charles is watching. Archer demands angrily that Charles give him an idea of what to do and storms off.

Charles talks to the twins and suggests that if Emma has a baby, it's like both of them having it because they are genetically identical. Gemma agrees to the ovarian surgery.

The head CT comes back. Jasmine has had a small stroke. This often happens to kids with sickle cell if they don't get regular screenings and treatment. The previous doctor never told the mother this. She is upset and blames herself. Hammer and Scott blame the doctor. Out of the patient's earshot, Scott says this happens a lot to kids with sickle cell, while cystic fibrosis patients, most of whom are white, get proper treatment. Hammer is upset.

Archer complains that Charles gave in to a patient's fantasy. Charles points out you can't give psychiatric treatment to someone who is dead and he did what he had to. Archer is mad for a change.

Another patient comes in needing intubation and Vanessa is called to help her, giving Goodwin the chance to ask Maggie how things are between her and Vanessa. Maggie is trying to keep her distance. Maggie is called away and Goodwin asks Will about Cooper. WIll updates her and she says he will find a way to make Cooper want to have drinks with him.

Will and Marcel's patient takes a turn for the worse. Marcel wants to replace the valve. Will says it is an overflow problem. They argue and Will accuses Marcel of wanting to charge more to Medicare. Marcel is offended. Will apologizes and Marcel says it's his patient and he'll do what he thinks is best.

Cooper finds Will observing the surgery and suggests Marcel use the VASCOM machine he allegedly is getting kickbacks from. Will tells Marcel, who is not interested. Cooper apologizes and tells Will that Marcel will come around and then leaves. Meanwhile, another surgeon assisting discovers that Will's diagnosis was right and Marcel changes direction on the procedure he was going to do.

Maggie suggests Jasmine's mother go get coffee. When Alicia stands, she is in a lot of pain and almost collapses. The doctors insist on examining her. She has severe arthritis in her knees and her doctor told her to take Tylenol. They give her an injection of pain meds and Stevie asks if Alicia is sleeping in her car. Alicia is offended but Stevie has seen this before and says that they just want to help. Alicia admits she is. Outside, Scott is impressed. Stevie is surprised that a cop didn't pick up on someone being homeless since cops chase homeless people off all the time.

Will goes to see Goodwin. He can't do this. If this is a condition of him working here, he's out. Goodwin had a feeling he would feel that way. She shows him the file of a young man who lost a leg after getting an infection from the insertion of the machine. If this machine was not needed, that was a preventable tragedy.

Surgery begins on Jemma, but Charles goes to talk to Emma in the waiting room and discovers the twins switched places (what good would that do? Emma would still be dying...) Charles rushes in sans mask to tell Archer to stop the surgery -- it's the wrong twin.

The little boy with the snakebite is being released. Scott tells him that a cop he knows will be watching and if the boy hangs out with gang members anymore, will tell the boy's father. The boy's father comes to pick him up and wonders how he got a snakebite. They will talk when he gets home. Scott tells the boy to stay safe -- people care about him.

Marcel and Will talk. Marcel acknowledges Will was right. Will tells him Nat's mom is doing better mostly thanks to Marcel. Marcel appreciates that. Both men admit they miss Nat.

Archer tells Charles that he's glad that Charles caught the switch before he removed a healthy ovary so that's a win. He says he can tell Charles is wondering if he is genuine -- hazard of being a shrink.

Archer compliments Scott and Hammer on their work with Jasmine and her mother. Scott tells Hammer they are going to get Jasmine into a clinical trial at Med.

Hammer goes to a homeless encampment. Her mother lives in one of the tents and is ill. She needs meds but doesn't want to get off the streets.