Atlantis Endgame (Time Traders)

In Earth's future, when time travel has become possible, the Time Patrol is the top secret government agency that protects Earth's past, so that our history will not become corrupted by invaders from either our future or from other worlds. For many years, Murdock, Ashe, and other members of the Time Patrol have contended with threats to our time continuum, none more deadly than the aliens nicknamed "Baldies", whose distrust of other high-tech civilizations has driven them to a destructive strategy.

In the seventh entry in the Time Traders series, Ross Murdock, Gordon Ashe, and the rest of the Time Patrol travel back to ancient Atlantis.

Evidence of time travel has been found in ruins dating to the ancient world, which is believed to be the legendary realm of Atlantis.

The Time Patrollers deck themselves out as foreign traders to discover that the Baldies are there, their purpose mysterious.

In the meantime, increasing tremors point to imminent apocalyptic cataclysm. But the time agents must remain until they resolve the mystery of the aliens' intent. If they're wrong, it'll be too late...for them and for Earth's future.