The doc is on a freighter to Alaska, with a plan to make a lot of money in a short time. It begs the question of how he intends to do that. We can assume it involves nothing illegal, such as the payroll heist he lied about last week. Maybe there is a high stakes skeet shooting event he can enter. Maybe a chess tournament. Maybe a bare knuckles fighting thing where he can beat a bunch of lumberjacks. Maybe he plans on winning the Iditarod. Maybe he plans on being a gigolo. He's about 60 years late for the gold rush. There really should have been a part 2 to this one to see what his plan was and whether it was successful. Anyways, a new passenger joins the voyage and the dramatic music and the way he looks at everyone and the way everyone looks at him is a dead giveaway that this guy means trouble for someone. All of the passengers and even one of the crew is hiding something. The shadiest guy is apparently Larry Tate, who has embezzled money from McMann and Tate. Larry is also a person of interest in the disappearance of Darrin Stephens the first. Turns out the guy is there to arrest someone who sabotaged a secret mission in the Korean War. He apparently doesn't who who he's looking for, but he somehow knows they're onboard. They put him in Kimble's quarters, and he is soon murdered. Kimble's identity is called in question, since his backstory is proven to be a lie. He is going to be turned over to the authorities in Ketchikan so he has to solve the case before then. Kimble channels his long dormant but still formidable sleuthing skills from when he was Richard Diamond, private detective, and sets a trap, which reveals the identity of the killer as Tate's wife, Louise, who sold out the mission for money. One passenger, who has eyes for Dick, tells him you never know who you're talking to. He gives her a "if you only knew" look and goes off to make a lot of money in a short time.
Worth noting: this is the only episode which features narration from William Conrad in all four acts.