Two members of a criminal gang are arrested and
imprisoned. Each prisoner is in solitary confinement
(keep) with no means of speaking to or exchanging
messages with the other. The police admit they don't have
enough evidence to convict the pair on the principal
charge. They plan to sentence both to a year in prison on
a lesser charge. Simultaneously, the police offer each
prisoner a Faustian bargain. If he testifies against his
partner, he will go free while the partner will get three
years in prison on the main charge. Oh, yes, there is a
catch ... If both prisoners testify against each other, both
will be sentenced to two years in jail. The prisoners are
given a little time to think this over, but in no case may
either learn what the other has decided until he has
irrevocably made his decision. Each is informed that the
other prisoner is being offered the very same deal. Each
prisoner is concerned only with his own welfare—with
minimizing his own prison sentence.