A planet with a small Federation science outpost and ancient Sakethan burial mounds, attacked in 2370 by Arctus Baran's mercenaries in their hunt for Romulan artefacts.
Calder II is a Federation world known to archaeologists for its Sakethan burial mounds, sites nearly two thousand years old. It appears in the seventh-season Next Generation two-parter Gambit.
In 2370 Picard, working undercover as a smuggler named Galen aboard a mercenary ship, and Riker, held there as a prisoner pretending to turn renegade, both learn that the next target is Calder II. The outpost there has only light defences. Riker contacts it and tries to get the staff to lower their shields, and when that fails the mercenaries open fire.
The Enterprise-D arrives during the attack. With Data in command, the ship trades staged shots with the raiders after Riker transmits what appear to be his access codes, allowing the mercenaries to escape with artefacts while keeping the two officers' cover intact.