The Trinity Treaty — Anita K. Mitchell

While studying a newly discovered type of planet, the Aldrin crew learns that sometimes the most beautiful things in the universe can be the most deadly. As they play host to a group of uncooperative diplomats sent by the Earth Defense Union to negotiate a treaty with Thera, the Aldrin Marines uncover a grudge that spans thirty years. When jealousy and hate are allowed to fester for so long, they can have explosive and deadly consequences.