Time travel has been invented and the US government forms an agency to regulate the technology and protect against bad people trying to change the time line. Walker (Jean Claude Van Damme) is one of these "time cops", we see him travel back to the 1920s to stop a rogue ex-colleague manipulating the future stock market. He warns Walker that a powerful man is forcing him (and others) to work for him, using the threat of literally wiping out their families from time...
Walker soon discovers that US presidential hopeful McComb (Ron Silver) is the man behind these crimes, stealing money in the past in order to fund his campaign. McComb is trying to destroy the time cop agency, and was also behind the death of Walker's wife (Mia Sara) some years before...
A good science fiction action film, it doesn't get too hung up on how unrealistic the science is but uses the effects budget well when required. There is also plenty of action, a good evil bad guy and plenty of humour. Entertaining indeed.