From Diablo Wiki
Stranded was a minor quest located in the Howling Plateau area of Act II. It was playtested at Blizzcon 2009, and the version in the final game will probably differ from what was seen in that demo build. (This quest name is tentative, and may be different in the final game.)
Stranded is a fairly simple “rescue and defend the NPCs” type mission. It took place in the ruins of a small town in the desert wastes.
The quest was given by an NPC soldier, a Captain who asked the player to find the rest of his men and help them fight off the attacking monsters. There were five other soldiers around the area, within a few screens of each other, and each was engaged with some Lacuni or Fallen when spotted.
Once each soldier was "rescued" he would run after the player and help fight against any monsters that came into sight. Once all five soldiers were located the player had to run back to the Captain, who gave his thanks and a small reward of experience and gold.
The best part of this quest comes after all the soldiers have been reunited. The Captain thanks you for your help and gives you a reward. A few seconds later, once the player has started to walk away, the soldiers begin shouting for help as a horde of monsters come streaming in from the desert.
This assault is a lot of fun to repel since the soldiers are in a large outdoor ruin (the area covers more than one visible screen) with only two narrow gateways leading into it, on opposite sides of the ruins. Thus the monsters can only come in one or two at a time, from two different directions. A single player completing this quest is thus forced to defend one gate, dash over to the other when there's a lull in attackers, dash back when more shouts for help come from the other direction, etc.
In the Blizzcon 2009 build, dozens of Lacuni huntresses came in one gate, while dozens more Fallen Imps came through the other. The monsters came in surges, seemingly timed to force a single player to rush back and forth in order to keep the hapless NPCs alive.
The quest did not have to be done in the precise order. If a player found one or more of the stranded soldiers before they talked to the Captain, the soldiers would still follow. They didn't speak though, and it wasn't until the Captain was located that the details of the quest were given. The Captain's speech did not differ even if you first spoke to him with several of his soldiers already in tow.