The novella “Diamond Dogs” by Alastair Reynolds was published for the first time in 2001.
In Chasm City, Richard Swift is contacted by his old friend Childe Roland, who was given up for dead for over a century and a half. He hasn’t even have time to recover from the surprise that Roland proposes him to be part of a group that wants to explore an artificial alien structure, the Blood Spire a mysterious tower found on a distant planet.
Richard meets the other members of the group, among which is his ex-wife Celestine. However, he he doesn’t remember her because he had the memories of the period of their marriage blocked. They travel to the planet where the structure is located and around it there are the remains of other explorers. The Spire contains a series of rooms and in each there is a test that requires an answer to enter the next room. A wrong answer will cause a violent reaction from the structure.