It Takes a Thief (1968) - 3x01 - Saturday Night in Venice- Followmy.tv

Al steals a computer memory core, the key to the entire military coding complex, from the Russian consulate. The Russians want it back. Lita, a Soviet assassin, slips a complex protein poison into Al's drink which gives Al less than 40 hours to live. Al finds Dover to make a deal to give back the memory core for the antidote, but Washington refuses, so Al does whatever he has to do to live, even if it means stealing the memory core back from the S.I.A. and giving it back to the Russians himself.