Undefeated is one of several stories in Halo: Tales from Slipspace. It was written by John Jackson Miller and drawn by Eric Nguyen and it follows the story of the UNSC Nereid's crew during the events of Halo 5: Guardians.
In October of 2558, the UNSC Nereid, a mixed cargo hauler ferrying a platoon of marines and a group of construction workers, is abruptly dropped out of slipstream space when its systems are impeded in the wake of the Created's galactic subjugation. Stuck onboard the ship in zero gravity, Lieutenant Commander and engineer Elaine Coffey, Lieutenant Rasul, and Major Kell Tanris try to make sense of the perceived cyber attack and attempt to contact the vessel's commanding officer, Yance. Worried that potential hostile forces could board the ship to acquire their nuclear ordnance, Tanris arms herself and asks Coffey to lead them to the Commander's location. Arriving at the Commander's private quarters, Coffey and the troops discover Commander Yance had drowned bathing in his jet shower while the water was unable to drain in the zero-g environment. Assuming the chain of command, Coffey advises everyone to work together with Rasul and Kalanga's construction crew to help power any vital systems while they attempt to hold out being stranded adrift in space. Although Major Tanris and Sergeant Chan dislike the idea of waiting out and would instead prefer to plan defensive measures for their cargo, they put aside their reservations and cooperate with Coffey's orders.
As weeks go by, the Nereid remains isolated, decades away from any contact with the UNSC. While all personnel onboard initially cooperate to keep oxygen and water filtration systems operating, Tanris and her troops soon become restless and decide to take matters into their own hands. Taking every bit of the ship's spare cabling, Tanris and Chan tell Coffey their makeshift plan to jumpstart Nereid's slipspace drive by linking it to their cache of nuclear-powered Hornet mines as a sort of radioisotope thermoelectric generator. Although the engineering crew protest the crude idea, Coffey relents and allows Tanris and Kalanga's construction crew to carry out the attempt. Days later, the plan to activate the slipspace drive fails and tempers immediately flare between the ship's officers and the marines. After Coffey intervenes and calms the situation, Tanris and Chan discuss taking full charge of command if things aboard the ship worsen.
Not long after, the ship's crew becomes unsettled when a disheartened construction worker throws himself out the airlock into the vacuum of space. Kalanga soon reports to Coffey informing that Tanris has deployed guards to take control of the ship. In order to gain leverage during the mutiny, Coffey and the engineering crew arm themselves in the cargo hangar containing a Hyperion warhead. While both forces face each other inside and debate on the proper course of action, Tanris questions the possibility of using their supply of nuclear warheads to help propel the starship ahead faster. Coffey confirms that nuclear propulsion will work with the help of some ship modifications and requests for everyone's cooperation in carrying them out. With both sides united behind Commander Coffey's plan, all of Nereid's personnel work to put her plan into effect.
Several days later, while Coffey drinks liquor and observes the operation underway, Tanris confronts her at gun point and threatens her with a court-martial for misleading everyone. After having spent a few days analyzing the Hyperion yields against the ship's shields, Tanris discovered Coffey's plan would actually destroy the ship and kill everyone on board. Coffey then reveals that she knew Tanris' idea wouldn't work, but saw the opportunity to give both their crews a goal to strive for, instead of having them suffer and die fighting for dwindling ship resources. Tanris comes to the realization that Nereid's crew is better off dying with undefeated hope than to keep fighting for a lost cause. Stowing away her side arm, Tanris joins Coffey in drinking and discussing the need for hope, even false hope, in times of war. Both women drink to hope as they await the ship's inevitable self-destruction.
Technology and equipment