The 2371 Romulan attack on the Federation's Amargosa observatory, made in search of stolen trilithium and leading to Soran's destruction of the Amargosa star.
The attack opens the main story of Star Trek Generations. The Enterprise-D answers a distress call from the observatory and finds most of its staff dead. Among the few survivors is the El-Aurian scientist Tolian Soran. A dead Romulan is found, and the raiders prove to have been looking for trilithium taken from one of their outposts by the Duras sisters on Soran's behalf.
While Data and La Forge search the station, Data's new emotion chip overwhelms him with fear, and Soran seizes La Forge. Soran launches a trilithium probe that halts fusion in the Amargosa star, and its shock wave destroys the observatory.
Soran escapes to the Duras sisters' Bird-of-Prey with his captive. The star's collapse shifts the course of the Nexus ribbon, the first step in his plan for Veridian III.