Systems of Secrets - M. B. Smith - Bog

Peace has again settled over the Laima System. King Aden of Kealt and Earth Alliance officer Abby Watanabe are looking forward to their oft-delayed wedding, when she is recalled to Earth to resign her EA commission, and he is summoned to Seti by his sister Celesta.
On Seti, Celesta informs Aden they've finally figured out purpose of the alien device the Ardalans discovered on planet XR564 during the Zon War. It is a doorway to the multiverse, through which its creators fled millennia ago to avoid their imminent destruction. When an accident causes Aden to fall through the doorway, he finds himself 20 years in the future and stranded on an alternate version of Seti, surrounded by slaughtered taals, the powerful and enigmatic rulers of Seti.
Determined to get home, Aden must find his new realty's version of the alien device. Little does he know he's about to embark on a journey that will take him to multiple worlds across two galaxies, meet long-dead friends, and learn shocking things about himself!