Original Time Masters
Rip Hunter was an inventor who created a time machine. During an experiment, Rip stranded himself and several others in the 25th Century, in a world recovering from a nuclear war. Back in his own time, Rip deduced that a group of oppressors called the Illuminati would be responsible for this devastanting future war. Because Rip's method of time travel could be used only once, he gathered a team - the Time Masters- to travel on his behalf and thwart the Illuminati.
Rip enlisted Bonnie and Corky Baxter, his cousin Dan and Tony, a computer expert. When Hunter's lab was destroyed by the Illuminati, the team relocated to an underground base belonging to Cave Carson, Bonnie's lover.
One of the Linear Men, Matthew Ryder, later brought the Time Masters to the Vanishing Point, a platform from which they could study disruptions in the space/ time continuum. After helping the JLA defeat Gog, the Time Masters were erased from existence.
Current Time Masters
Rip Hunter formed a new Time Masters team when Batman (Bruce Wayne) was lost in time. This team consisted of himself, Booster Gold, Green Lantern Hal Jordan and Superman. Everyone knew that Bruce was lost in time, however no one knew how to retrieve him from the time stream. Bruce Wayne traveled through the first days of man (cavemen), witch hunter, pirate, cowboy, and a private eye detective. However, the Time Masters encountered an Omac like being, who stopped them all from trying to save Bruce Wayne. While Bruce continued his journey through time, the Time Masters had to find an alternate route to get Bruce back. Through their journey together, the team encountered friends and enemies alike, like Claw and the mind controlling alien Despero. Event after event, the Time Masters continued to be thrown off of the trail of Bruce Wayne, eventually by the end of Return of Bruce Wayne the Time Masters reached their final destination. They arrived 8 minutes behind Bruce Wayne, and the Omac like robots had already taken control of Bruce's body.
The Time Masters didn't want them to destroy the entire universe, so Bruce had to battle this being inside his mind, eventually defeating it and returning to modern times with his friends and family. Rip Hunter decided to keep the Time Masters active, and they are currently protecting different times from evil super villains that might want to destroy or control the world!