- "Find Private Mills and take him with you! Get him to free up the bloody thing!"
- — Cpt. Price
Around the time of the Allied invasion of Normandy, Mills was assigned to D Company, 2nd Battalion of the Oxfordshire and Buckinghamshire Light Infantry. Under the command of Captain Price, his unit landed via glider on the eastern bank of the Caen Canal undetected. Upon attacking, the British paratroopers swiftly dispatched the German sentries and pushed across the bridge into Bénouville. After establishing a front line on the western bank, the unit was ambushed by a German Panzer IV. On Captain Price's orders, Evans and Mills sprint back across the bridge to a disabled FlaK 88. As they reached it, under fire, Mills freed up the fire controls of the gun, allowing Evans to man it and destroy the Panzer. Immediately afterwards, the unit pushed the German defenders out of Bénouville, securing the bridge within minutes.
Mills can be killed during fighting that morning, or during the artillery barrage preceding the main German counterattack.