Tessic was a member of an alien species and the leader of a colony that mined deuterium in the 22nd century. Enterprise NX-01 visited the colony in 2152, seeking to buy or trade for deuterium. Tessic at first wanted nothing to do with the visitors and asked them to leave. After negotiations with Captain Jonathan Archer, Tessic agreed to give him the deuterium in exchange for medical supplies, power cells and assistance in repairing the colony's extraction pumps, but told Archer that they had to leave in two days. Tessic was trying to hide the fact that Klingon marauders were preying on the colony, taking the deuterium, leaving just enough for the colonists to survive.