Finished “Section 31: Cloak” by S. D. Perry.

The Enterprise is on its way to a science conference at Deep Space Station M-20 when it picks up an automated distress call from a runaway starship, the U.S.S. Sphinx, coming out of the Lantaru sector. They catch up to the Sphinx and manage to pull it out of warp, only to find that the entire crew are dead. There is also an unidentified individual aboard who is not on the crew roster. This stowaway was apparently killed on the bridge in a fight with the captain.