LEGO Time Cruisers is 1996 to 1997 theme which introduces time travel. Sets are based on two factions, The Time Cruisers and the Time Twisters and the underlying story revolves around a professor named Dr. Cyber's travels through time.
From the LEGO official description "The LEGO Time Cruisers sets will give you the chance to travel through time...anytime! Imagine navigating your vehicle through the depths of time, visiting other places past and present to complete your top secret mission! Careful though, as you never know who or what you'll meet! Most importantly, remember to get back home, or you could be trapped in time forever!"