The Enemy of My Enemy is the fifth chapter of Left Behind and its main combat chapter. With the medical kit in her pack, Ellie fights back across the Colorado Mountain Plaza to Joel's hiding place while armed survivors and infected roam the halls, and you can turn the two groups on each other.
Part 5 of 6 in Left Behind
1. Returning to Joel: from the helicopter through the halls and an air duct. 2. Fighting hostile humans and infected: the stores near the pharmacy and the last stand at the yogurt shop.
Gunshots in the distance tell Ellie that Joel may be in trouble. She packs the kit, jumps down from the helicopter and finds a photo on a soldier's body. From hiding she watches clickers tear into two men; the second kills one with his bow before he dies, and three more men finish off the last clicker. Take the bow and pick them off. An air duct further on holds a recorder and another body.
Past the duct, two men hide from a small pack of infected and wait for backup. You can let them fight it out, throw something to start the brawl early, or just run past. A fence then pushes you into another store with infected inside and four more men arriving, with the same three choices. A shutter beyond a metal container brings you back to the American Princess store and Weston's Pharmacy.
Ellie's pursuers have found the yogurt shop, drawn by Callus behind the shutter. Get their attention and kill them, then more pour in, one with a hunting rifle, until infected swarm the lower floor. Side with one group to wipe out the other, finish the survivors, and crawl into the shop to find Joel still alive.
The survivors hunting Ellie belong to the same group Joel and Ellie fought at the university, the people later revealed to be David's cannibals.
Back in a Flash
Back in a Flash is the first chapter of Left Behind. After a short flashback to Riley's surprise visit at Ellie's school in Boston, you play Ellie in the snowed-in Colorado Mountain Plaza, searching the mall for anything that can help Joel.
So Close
So Close is the third chapter of Left Behind, back in the present at the Colorado Mountain Plaza. Ellie has to restore power to reach the crashed military helicopter on the mall's upper level, which means siphoning gas for a generator, fighting stalkers in a flooded stockroom and sneaking through a pet store full of infected.
Escape from Liberty Gardens
Escape from Liberty Gardens is the final chapter of Left Behind: Ellie and Riley run from a horde of runners through the Boston mall, climbing scaffolding to find a way out. It has no collectibles, and finishing it unlocks the gold trophy Don't Go.
Fun and Games
Fun and Games is the fourth chapter of Left Behind and the busiest one for trophies: Ellie and Riley ride a carousel, wreck a photo booth, play pretend in Raja's Arcade and hold a water gun fight inside Liberty Gardens. Along the way Riley finally explains why she brought Ellie to the mall.