In "Field of Fire" a search for a serial killer aboard Deep Space 9 begins when three Starfleet officers are shot dead while locked in their own quarters. Investigating the killings, with the help of her own murderous past, Ezri Dax is shocked to find that hers is the next name on the killer's list. In "Chimera" a Starfleet Runabout is boarded by an unknown shapeshifter and Odo recognises the intruder as one of "the hundred" Changelings who were sent alone into space hundreds of years previously. Odo convinces the changeling not to join the Founders, but the new arrival's hostility quickly leads to bloodshed.