Mac Connor is a biologist; she studies salmon migration in the nature preserves of the Pacific Northwest. (Halfway between Vancouver and Moose Poop, Nowhere.) Earth has made contact with cordial aliens, imported a bunch of alien technology, started a bunch of offworld colonies, and is generally paradisiacal. Mac's biggest problem is wrangling permission to set foot in the (highly protected) Castle Inlet Wilderness Trust, which, everybody agrees, is supposed to be a hassle.
Then a big blue alien shows up asking about her work, which puts hassle in everything. The Dhryn is cheerful and oblivious to politics, but comes with, er, blivious political handlers. They know more than they're saying. So does the Dhryn. So does the Ominous Prologue, in which a forest is melted down by green slime from outer space.
Thus, a big wacky interstellar spy story, crossed with first contact. (It's not actually first contact with the Dhryn, but they've been reticent about trading information with other species, so Mac's journey among them can indulge in first-contact tropes.) Both sides of the cross are competent and engaging. They're supported by quite excellent characters; all the stars are vivid, from workaholic Mac to her outrageous research partner Emily to the convincingly nutso crowd of academics and grad students surrounding their field base. The alien manages to be charming and funny without being human. The inevitable (human) love interest is somewhat shortchanged by being out of commission for most of the book, but he does not appear to be a jerk, which is nice.
The alien spy hijinks turn into alien spy serious problems, and the oh-shit level climbs quite high by the denoument -- melty green slime is nobody's friend. A trilogy is set up. I am up for it.
(I wondered how the Dhryn are quite so clueless about biology, but this is more or less addressed by the end.)