Sean, Evie, and Gosia are called out on a medivac to treat a nine-year-old boy with a broken leg but instead find a group of homeless kids living in an underground sewer complex and a middle-aged man with an unknown illness. Returning to the hospital, Sean and Evie eventually diagnose the man as having an obscure 16th century sweating sickness and convince Arch to let them treat him with an equally obscure 16th century remedy. After their brief first encounter in a bar, Marina becomes a strange man's object of affection as he sends her flowers and begins to hang around the hospital. Tom refuses any cancer treatments that may prevent him from returning to work, but an unsympathetic Arch just wants him to be replaced.