A top-secret government weapons designer is arrested by a clandestine government organization on suspicion of being a clone created by the hostile alien race wanting to take over Earth.

Detectives Nick O'Malley and Kate Benson work in Special Unit 2, a secret precinct of the Chicago Police Department whose sole charge is to protect the city's citizens from Links, a malicious paranormal species that is the missing link between man and beast.

Workaholic Mike Flaherty is the Deputy Mayor of New York City, serving as Mayor Randall Winston's key strategist and much-needed handler. Mike runs the city with the help of his oddball staff: an anxious and insecure press secretary; a sexist, boorish chief of staff; an impeccably groomed gay activist running minority affairs; a sharp and efficient, man-crazy accountant; and an idealistic young speechwriter. Like Mike, they are all professionally capable but personally challenged.