Ocett's need to solve a four-billion-year-old genetic puzzle for an unlimited power source brought her to Loren III, along with the USS Enterprise-D and the Klingon Vor'cha-class attack cruiser IKS Maht-H'a. After an agreement was made between the three ships, Ocett beamed to the Enterprise-D to discuss the matter of the puzzle. During the meeting, she tried to hide the fact that she was carrying a piece of the puzzle, claiming she was scouting the planet for possible colonization. Captain Jean-Luc Picard, however, called her bluff and it was found out all three species had a piece of the puzzle. Agreeing to a cooperation for scientific research, Ocett surrendered her sample which eventually led to one piece remaining.
However, this cooperation did not last. After being told that the final piece was located in the Rahm-Izad system, Ocett quickly transported to her vessel and it, along with its sister ship, fired on the Enterprise-D and the Maht-H'a's engines. Thinking that the ships were crippled, Ocett quickly left the area to find the final piece. The Enterprise-D crew, however, had anticipated her betrayal and were ready for the attack. Undamaged, they proceeded to the true location of the last piece, the Vilmoran system.
Eventually realizing that she had been tricked, Ocett was able to intercept the Enterprise-D. She beamed down to Vilmor II with a guard and attempted to take the final sample from a rock face, but her plan was further thwarted by Romulans who had been shadowing the three species' efforts. To prevent the Romulan away team from leaving with a sample, Ocett threatened to destroy the rock face. These actions led Ocett to a standoff against the Romulans and the Klingon Captain Nu'Daq, while Jean-Luc Picard and Beverly Crusher secretly finished the puzzle.
To Ocett's surprise, the puzzle was a message stating that all species were created from one being. She was greatly disgusted that she was related to Klingons and left dissatisfied. (TNG: "The Chase")
Ocett was played by actress Linda Thorson. When she introduces herself to Picard, however, Thorson pronounces the character's name "Osech." This may have been the original name, but it was never correctly looped.
Ocett was the only Cardassian female with the rank of gul to appear in Star Trek.
In Andrew Robinson's DS9 novel A Stitch in Time, it is mentioned that Ocett was a cell leader in Damar's resistance, and the only such leader to survive. Her actions were also critical to the outcome of the Dominion War, convincing the Cardassian Fleet to turn against the Jem'Hadar. The novel also gives her first name as "Malyn".
According to the Star Trek: Terok Nor novel Night of the Wolves, she entered the Cardassian military as she was unable to have children. By 2345, she had achieved the rank of dalin and was placed in command of the Kevalu. During that year, she discovered a spherical module in the Denorios Belt which contained an organic, gelatinous lifeform who came to be known as Odo.