"No Regret begins 46 hours after the events in No Remorse. A WEC freighter headed for the Moon picks up the Silencer's escape pod, and the Captain, upon moonfall, makes contact with the local Resistance. The WEC uses the moon as both a mine and prison, where most of the political dissidents and Resistance members are forced to extract a precious radioactive compound, Di-Corellium. This mineral is the basis of virtually all energy production on Earth. Approximately half of all known reserves are on the moon, and a shortage of Di-Corellium would cause serious problems for the WEC. For this reason, Chairman Draygan is on the moon to oversee the Di-Corellium production, which has been lagging recently—possibly due to incursions from the Resistance cell on moon, at the hidden Dark Side base. He is, to say the least, not happy when he learns that the Silencer appears to have survived and may well be on the moon."
Source: Wikipedia, "Crusader_(game_series)," available under the CC-BY-SA License.