Derelikt

Hired as a one-person expedition into the carcass of a gigantic space creature discovered in orbit around Saturn, you descend into its ancient bone structure. A research outpost was grafted onto the exterior years ago, and the scientists there are nervous, paranoid, and speaking of something they call the old song — a sound worming its way into their thoughts. Armed with a security weapon and a foreboding feeling, you enter the service elevator and begin your descent.