Star Trek IV: The Voyage Home (1986)

There’s no traditional antagonist such as Khan or the Klingons or the Borg, and no big fight scenes or starship shootouts. Instead, the action is driven by a conceit as endearing as it is goofy, with shades both of 2001: A Space Odyssey and The Hitchhiker’s Guide to the Galaxy (and how many films can you possibly say that about?).

A mysterious alien probe, reminiscent of 2001’s monoliths not only its general size and shape but also in its impenetrable purpose and workings, is approaching earth, sending out a signal wreaking havoc on the biosphere and on communications systems. The devastation will be catastrophic unless humans can find a way to respond to the probe and get it to stop bombarding the earth.

However, in an Adamsesque twist, it turns out that the probe’s communications aren’t intended for humans at all, but for another species: not dolphins or even mice, but humpback whales, unfortunately extinct in the 23rd century. Before you can say "So long and thanks for all the fish," the Enterprise crew is off on their benign whale-hunting expedition into the past, a conceit that is not without its flakey side but has undeniable charm.

The Voyage Home is the conclusion to the "Spock Trilogy" begun in Trek II: The Wrath of Khan and continued in Trek III: The Search For Spock. (Note: Trek II-III spoilers follow.)

Heroically sacrificing himself for his friends at the end of Wrath of Khan, Spock was fortuitously rejuvenated and ultimately restored in Search For Spock, but the return of this beloved character would have seemed abrupt and unsatisfying if the series hadn’t allowed for a kind of readjustment period for him and his friends. The Voyage Home meets this need, while also providing some of the most humorous and humane moments in the Trek canon.