The Whispering Tombs
The first book in the Quality Times series.
When an archaeologist alien invites you on a quest to discover hidden treasure, you don't say no. And the fact that his handsome, blue-skinned assistant will be along for the ride, is an added bonus.
For space and time adventurer, Quality Times, the chance to go exploring in the caves of Azrokaran is too good an opportunity to refuse. But a startling discovery leads to a trip back in time, and loyalties are tested to the limits as those within the group reveal their true colours.