The forces commanded by the rogue Grand Admiral Demetrius Zaarin laid in wait and ambushed the loyalist Imperial forces within the Semag system.
The renegade Grand Admiral Zaarin discovered that Grand Admiral Thrawn was attempting to ensnare him, using a small convoy supposedly laden with Missile Boats as bait. In response, Zaarin deployed a small strike force with orders to annihilate the convoy. Thrawn, suspecting the presence of Spies in Zaarin's service, decided to use a convoy that genuinely carried Missile Boats. Regrettably for Thrawn, Zaarin anticipated this tactic and intercepted Task Force Whirlwind. This task force was comprised of the Interdictor Whirlwind along with 4 Strike Cruisers: G'Neeznow, Indomitable, Iron Duke, and Triumph. Zaarin employed his own Interdictor, the Maelstrom, supported by TIE Advanced fighters to engage the enemy fighters and TIE Defenders to assault the Whirlwind.
Tan Maarek Stele, piloting his personal Missile Boat, was a member of the task force. He engaged the opposing fighters, successfully eliminating several Advanced and TIE Defenders. However, some TIE Defenders managed to inflict damage upon the Whirlwind. Stele, despite the damage, intercepted the remaining rockets and eliminated the remaining enemy fighters. With limited time remaining, he launched Bombs with the intention of destroying the Maelstrom.
Although the attack represented a specific loss for Zaarin, he still achieved his objectives. The Whirlwind sustained damage and fell significantly behind schedule, allowing Zaarin to attack the convoy earlier than anticipated. Stele was the only individual capable of rescuing the convoy in time.