Sieges are special events which task players with capturing and defending objectives while fighting waves of enemies. Once a Siege starts, players have a limited time to increase their score by capturing objectives and by defeating enemies. Killing enemies enables you to progress through stages. Later stages have more enemies, more enemies means more points, more points mean better rewards!
To capture a point, the growth around the point must be destroyed. Once that growth is destroyed, the point is captured for friendly forces. Enemies attacking points will capture the points for their side. Standing near a point, previously attacked by enemies but not captured, will capture it for friendly forces.