Walker and Alex are trapped on board a crashed plane that sinks to the bottom of a remote lake.
A "dirty" cop tries to kill Alex after she receives insider information about a ring of Dallas policemen who are stealing confiscated drugs drom the evidence lockers and reselling them on the black market.
When a protected witness is killed while Walker and Trivette are guarding him and a mobster may be released from prison as a result, Walker goes undercover as a convicted assassin in the maximum security prison to force a murder confession from the mobster.
Tragedy intervenes when Alex is shot by an ex-convict, who holds her responsible for putting him in prison, just as Walker is finally about to ask her to marry him.
Walker and a legendary ranger (Stuart Whitman) uncover a plot to assassinate a U.S. senator (Ben Masters); guest Jonathan Banks.
