A children's picture book.
The Enterprise receives a distress signal from the fifth planet of the star Fomalhaut--it seems that dinosaurs are terrorizing the populace, destroying their cities. The Enterprise rushes to their aid, and Kirk, Spock, and McCoy beam down to investigate.
There are no dinosaurs. Instead, they encounter Colonel Kragg, who informs them that his armies are prepared to take over the universe--as soon as they learn the secret of the Warp Drive. And they will get it, too: they have a machine that can force a man to tell the truth.
Spock volunteers to be subjected to the machine, on the theory that if any of them can resist, it will be him, but it seems that his plan has failed. On command, he draws up plans for a warp engine.
In only two days, an engine has been built and placed into one of the Fomalhaut warships, but when they test the ship--it explodes! Spock has told a lie of omission--he did not inform them that if the dilithium crystals were not cut just so, then their ships would explode.
In the confusion, Kirk, Spock, and McCoy are able to get the drop on the men of Fomalhaut, and return to the ship with Kragg as their prisoner.
A silly, simple story, with silly, simple language, but what do you expect from a picture book? As for the ending, well... we all remember The Enterprise Incident, don't we? As Spock said, then, "It is not a lie to keep the truth to oneself."