Seattle, 2060. Twenty years after a catastrophic earthquake left her effectively an orphan, exotic-animal specialist Sasha Delescu has returned to the rebuilt city of her birth for a new job, and, she hopes, a new chance at taking on the personal demons that have dogged her since her childhood tragedy.
The job, an internship with space-exploration company Xenobiology Network, is great at first. She gets to put her education to use studying newly retrieved samples of extraterrestrial life, and meets new friends Alex, a physics genius and fellow intern and Jay, a former soldier and the company's security chief. Even her old pain seems to be fading, as she reconnects with a beloved relative and begins to regain a sense of the family she lost.
Then the crash changes everything.
Appearing seemingly out of nowhere, an alien ship streaks through the night sky over the city, eventually crash-landing in Elliot Bay. After further investigation, Alex discovers the frightening truth: The craft came through a previously unseen rift in the universe-a doorway to a distant planet. More alarming still, there are more of these doorways, which he calls tesserae, everywhere all over planet Earth, and they're opening all the time.
The original study with the alien samples now abandoned, Sasha, Jay, and Alex must suddenly switch gears, helping XenoNet to manage tesserae incursions from aliens both beautiful and dangerous, while also trying to manage their increasingly complicated feelings for each other.