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At the Fall of Tarsonis, Arcturus Mengsk ordered Darabont's unit to hold back, contributing to the fall of the planet to the zerg. As a result, his unit was branded a coward, and made to wear a yellow slash on their insignia.
The next year, Darabont was ordered to take the Cyrus to the Ghost Academy, and take a number of ghost trainees to The Baker's Dozen, apparently not being told there were four survivors from the Old Families there. Darabont let the trainees know he didn't like them.
A trainee detected the Old Family transmission from Shi. He and other ghosts broke onto the bridge and told Darabont about this. The commodore was initially uninterested until told there were zerg there too. Over trainer Lagdamen's objections, Darabont intended to travel to Shi and use the ghosts in combat. Darabont and Executive Officer Mirne, wanted to redeem themselves for what happened at Tarsonis.
The marines landed first on Shi, defeating a wave of zerg. However, they were overwhelmed from hatcheries south of Mandible Canyon. Darabont ordered the use of Apocalypse-class nukes, which the Cyrus carried several of. However, these ones had to be guided by ghosts. The hatchery cluster was destroyed.
The ghosts and marines found themselves inundated with yet more zerg coming from a larger cluster of hatcheries on the far side of Mandible Canyon. Darabont sounded the retreat, giving them six minutes to head to the landing zone. The ghosts discovered the Old Family heirs. The terrans were dismayed, however, as their lander was destroyed by the zerg.
Darabont dismissed the losses and had the Cyrus moved toward the second cluster of hatcheries, intending to destroy them. The Cyrus was shot down by spore cannons. The zerg invaded, killing both Darabont and Mirne.