StarCraft/Zerg mission 8: Eye for an Eye

The Setup

This is a fairly complex situation. First of all, note the three beacons strewn out across the map, each guarded by an Overlord and some of your forces; if even a single Dark Templar steps on one of these beacons (thereby escaping), you lose the mission. Dark Templar are formidable foes on their own, possessing a ludicrous 40-damage attack and being permanently cloaked, but the Protoss will usually send reinforcements with them when they launch one of their periodic attacks on the beacons. So keep those Overlords there (to detect the Templar), and reinforce the troops defending those beacons until you have at least six Hydralisks near each.