You go into the prison of elders and there are 3 rounds. The main point is to kill the boss in each round, but there are waves of ads that appear, each wave being triggered when the boss has reached a certain point on his health meter. Getting kills earns you points, and when you have finished all 3 rpunds, you may get rewards from Variks if you get a high enough score. There are modifiers in place which will add to score, or make the challenge more difficult. For example, Grounded may be active, which will make Guardians take more damage whike airborn, and there may be a point bonus for super kills, so every time you kill an enemy with your super, you would get more points than if you got a regular kill. You can check the modifiers by pulling out your ghost and checking the active modifiers tab. As each round progresses, kills are worth more points. Round one a kill is worth 25, plus modifiers, round two they are worth 50, round three they are worth 75. You can also get points for assists, creating orbs and modifiers add to your score such as precision kill point bonuses. 30,000 is the point goal for the single-playthrough reward, so if you can get 5,000 in the first round, 10,000 in the second, and 15,000 in the third, you will be fine. Try and shoot enemies without killing them, and have your teammates do the same. This way, you get extra points for assists. Also try to kill as many enemies as possible in the manner that will give you point bonuses. For example, if the precision kill point bonus is active, have everyone shoot a bunch of enemies without killing them, then start killing them with precision kills. That way you will get points for assist, as well as the points for the kill, and the precision kill bonus. It's not as difficult as it sounds, I reccomend you go in and try it. Even solo, many people are able to reach the required score. Also, the bosses may drop exotics if you have a 3 of coins active, so it's a decent place to farm exotic engrams. Other drops may include the Dregs Promise, Queenbreakers Bow, and the Lord of Wolves as well as a class item that can drop as high as 335 light.