Alien Kill School (2nd in the "Related to the Knife" books)

Dr. Alice Mullen and her A.I. friend Hal are on a research mission further from Earth than any human has ever ventured. They land in the middle of a war to the death. Beings that destroy oxygen breathing life discover the humans and put them on their extinction list. Alice and Hal find themselves being the point men for the human race. If they fail, there will be no second chance.