Detective Murdoch investigates the sudden death of bicycle racer Joe Fenton. Murdoch was himself a participant in the race trying out his newfangled gear shifting device but Fenton was the favorite having won several recent races. Fenton's manager, Chippy Blackburn, was seen giving him a potion and they suspect he may be may be fixing races. Dr. Grace however is having considerable difficulty finding a cause of death and with Dr. Ogden's assistance performs her first brain bisection. It leads her to believe he suffered a cerebral aneurysm leading to a brain hemorrhage. The discovery of an injection mark in Fenton's right arm leads to a different conclusion however. Meanwhile, Julia prepares to sell Darcy Garland's house but finds that his younger brother Leslie living is living there.