From the back cover...

Here's the back cover for Highway to Tartarus:

Insanity seems to run rampant in the immortal population, and Hades seems to be the one the Fates tap to contain them all; however, this time, Hades, and Kyra, the former goddess of War from Atlantis, have to find and catch the one who's gone dangerously insane: Deshayna, Kyra's identical twin, and the former goddess of Death.

Along for the ride are a pregnant Persephone, Hel from the Norse pantheon (and Hades' and Persephone's lover), Tyr and Thor, and Kyra's adopted daughter Rowan. 

The seven of them follow rumors, leads, and death-god connections around the world in an RV that's bigger on the inside than on the outside, while trying to maintain a bare semblance of normalcy despite the chaos of never knowing when or where their Fates-assigned mission will end...or if it will end them.

 Give it a download and read.