Bates and Coffey take over a storefront police/community relations project; a cop killer seems to be roaming the streets; Daryl Ann buys the wrong motorcycle for Renko; Joyce behaves oddly about buying a house; Leo and Ray try out an unorthodox method to get rid of the rats; and Daniels tries to short circuit Cleveland's corruption task force by exposing a network within the special Vice detail.

The rats return; Esterhaus is hospitalized for tests; Bates, Coffey and Joyce try to protect a woman and her children from her abusive husband; the latest cop killing looks to be a hired gun copying the random killer; and the corruption investigation strikes close to Hill Street; Hill Street gets word of the murder of Marty Nichols.

Furillo loses an old friend as the corruption investigation winds up; a romantic triangle transfers to the Hill and comes to a boil; and Coffey gets shot by the cop killer.