Will and Robyn treat a diabetic cat lady who comes in after a heart attack but refuses treatment so that she can get back to her animals. Robyn diagnoses her with Toxoplasmosis, but she and Will are shocked when the woman still refuses to stay for treatment. When the woman is attracted to Daniel, Robyn concocts the idea that he may also have Toxo, leading him to share more about himself with his daughter.
Nina asks Will about his relationship with Nat, and he previcates, telling her that they never dating but failing to disclose his unrequited feelings for the pediatrician. He considers coming clean but in the end, sticks to his story. He ends up shocked and a little disappointed when his "honesty" leads to Nina sharing her past, which involves relationships with more than a few Gaffney docs.
April and Nat treat a young boy who is forgoing his latest chemo medications. At first they blame the father, but Nat speaks to the boy and starts to accept that not only is it the kid's choice but that he actually understands the decision he is making. April, in a hormone driven surge of protectiveness, calls DCFS to report the father. Remarkably, test results come back showing that his cancer is actually reduced despite the lack of treatment -- the break from chemo has allowed his immune system to strengthen and to fight off the cancer on its own.
Sarah struggles to understand and treat a patient who comes in claiming to have a "tulpa," wanting to find some tidy diagnosis for the woman so they can give her appropriate treatment. Charles eventually guides her to seeing that medicine is art and science and that even though she sees herself as an analytical scientist, she is more than adept at the compassionate, intuitive side of things as well.
Connor and Latham travel to Rock Island so that Connor can perform a rare surgery. He ends up needing an assist from Latham in the OR when the local docs question him extensively on the procedure, and he pays his mentor back by recovering his money and his watch after he is conned out of them by a bartender and an unscrupulous woman.