20000 Avant J.C. (f) (1987) - Amstrad CPC - Action

Humanity is being threatened with extinction by a deadly virus named X13. The only way to counter the threat is to travel back in time to 20,000 BC and reconstruct the virus. Secret agent Karl Adrix has been sent in a time machine to explore a prehistoric landscape, find the constituent parts of the X13 virus, and thus save humanity.