Trappist-1 is a star system about 39.5 light years away. The star is an ultra-cool red dwarf star in the constellation Aquarius, and it is found to have several earth-like planets with the potential to support life. Humanity sends a starship to explore the system.
The Forerunner One, a starship capable of traveling at half the speed of light, is outfitted with a crew that spends the 78-year journey mostly in cryogenic sleep. At half lightspeed, time on the ship moves 15% slower than it does back on Earth, due to relativistic time dilation.
But while all this is good stuff for a solid science fiction story, it’s not really relevant. As it turns out, the crew arrives at their destination, and without much thought or preparation (would you think?) they land on one of the planets, only to be attacked by the local fauna within a few hours of landing.
The local intelligent species is aviary. They are smaller than humans, about 4 feet tall, skinny, birdlike, and they can fly. The humans call them Avari. They have far superior technology compared to the humans, and within a day of arriving, having traveled most of a century, the humans are driven back to their ship and forced to flee – you get it – back to Earth.
Spoiler Alert:
It turns out that the Avari have technology to cloak themselves and even their ships. So they can be invisible. Two of them sneak on board of the human ship undetected and start wreaking havoc on the way home. Not only that, they breed a hybrid avari-human fetus in one of the females on board. Obviously, this sets things up for a lot of surprises on the trip home.
There is a twist at the end, which makes it clear that the entire book First Encounter is just there to be a setup for a series of books called The Ascension Wars, and this is Book 1.
I didn’t care too much about the writing style, the loose and unrealistic plot, and the shallow character development overall. First Encounter seems a little bit like pulp fiction, or worse, action hero comic book material. If you like light science fiction, this might be reasonable entertainment. But for me, I am done reading this series.

Popular first-contact books and movies are often pretty stupid. The Alien Series is an example. When a new life form is discovered, the humans want to play with it. Then when shit happens, they never observe quarantine protocols. In movies like War of the Worlds it is always our germs that kill the aliens rather than their germs killing us.