Sarah Long is a sonar research assistant aboard "The Lewis" in the western Pacific ocean. The ship is engaged in upper crust geological mapping of the seven mile deep Mariana Trench when they ping a large ship lying in the sediment at the bottom of the ocean.
On board the hidden ship, two officers are abruptly awakened by the scanning of their ship. Thousands more are still asleep.
This book drew me into the abyss from the start, I am looking forward to reading the rest of the story and its sequels.