A secret tryst threatens to turn two cops against each other Isaac Sidel is a bear of a cop. Although his position as the commissioner's first deputy is largely political, Sidel has not forgotten how to work the New York City streets. To protect the East Side he has survived gunfights, broken arms, and once tore out a hoodlum's eyes. In his spare time he does favors for old friends, finding runaway daughters and protecting merchants from roving street gangs. On the street there is no problem he can't solve, but at home he is powerless.   His daughter Marilyn, twenty-five and twice divorced, keeps Sidel up at night. Just before her father goes to Paris for a lecture on police work, Marilyn runs away from her newest husband and shacks up with Manfred Coen, Sidel's blue-eyed protégé cop. Both men love her, and when Marilyn becomes a target, they'll destroy the city to save her, if they don't kill each other first.