A rare infection forces Dr. Charles' (Oliver Platt) daughter, Robin (Mekia Cox), to appear in the upcoming episode 4, titled "Brother's Keeper," of the second season of the American medical drama "Chicago Med."

The hospital finds out that several of their patients have the same rare infection. To consult the patients and look into the situation, Dr. Charles' daughter, who happens to be a specialist in epidemiology, comes in. Meanwhile, things may not go as how the doctors want them to be since an elderly patient's son and a young girlfriend do not approve of his treatment. Dr. Reese (Rachel DiPillo), on the other hand, works hard to help a young drug addict fight against his addiction.

The promo trailer for "Brother's Keeper" shows the doctors fearing that a possibility of an outbreak that might not have a cure could put the patients' lives at risk. Dr. Manning (Torrey DeVitto) decides to step out and confess that it could be her fault due to a misdiagnosis. However, there is a much bigger problem that they may face. There is a possibility that one of the patients with the same infection may have been discharged and could cause an epidemic. The doctors seem to be facing one of the biggest crises in their hospital.

Meanwhile, Cox shared on Hidden Remote about her character Robin. She said, "She's very driven. She's kind of an overachiever and I think because of who she is, she always has to prove herself because she is the daughter of Dr. Charles. She feels like I did this on my own. He wasn't really around in her life after a certain age. [Medicine] is something I think she's wanted to do since she was a little girl... But she had to prove herself outside of her father."

"Chicago Med" season 2 airs Thursdays at 9 p.m. on NBC.