Gelrak V is a planet whose people attack the Cerritos after receiving the wrong diplomatic gift during Captain Freeman's strict deadlines.
Gelrak V is the destination the Cerritos is assigned in Temporal Edict, after being pulled from peace negotiations on Cardassia Prime to deliver diplomatic trinkets there instead. Captain Freeman, frustrated at the minor assignment, imposes strict time deadlines on every task aboard the ship.
The resulting chaos causes the away team to deliver the wrong gift, and the offended people of Gelrak V attack the Cerritos. The ship can only respond once Boimler persuades Freeman to cancel the deadlines and let the crew work in their own time.