Heart of the Swarm Campaign- Skygeirr: Hand of Darkness

Your second mission at the Skygeirr research base is the main point of having come here in the first place- the destruction of the Hybrid that the Dominion have been studying here.  Completing this mission will give you access to the evolution mission for mutalisks, and there are two additional Kerrigan levels you can pick up here from bonus objectives.  You are also warned by Stukov that there is an additional foe within Skygeirr- Narud, a shapeshifting servant of the ancient Xel'naga, Amon.  While within the base, you will have to face him as well- though when you will do so is not clear.

At the outset of the mission, your forces break into the base and establish a hatchery just within the gate.  This will be your main source of units while you're within the base.  Additionally, the first of the Hybrid breaches its containment and immediately begins psionically draining Kerrigan of her power.  This gives you an additional imperative to destroy the creatures- not that you terribly much needed one.

The exit to the platform your main colony is on waits to the Southwest, and due West of the colony on the next level down is the Hybrid that has already escaped containment.  You'll need to destroy it within four and a half minutes, or Kerrigan will be destroyed and your mission will fail.

Around the time you destroy the first hybrid, a small Terran task force will lash out at your main base, seeking to evict you from the lab.  This force is small, composed mostly of light units, and pretty easy to handle.  The real difficulty starts a short while afterwards- Naruud begins voluntarily waking up the Hybrids, starting with three in widely varying locations.  Thankfully, the waking Hybrids will be marked on your map although they are all some distance away.  The first to finish waking is to the Southwest, and it will immediately begin draining Kerrigan's power.  This one needs a full five minutes to take effect, which gives you a good deal of time to build up additional forces so that the later assaults will be easier.  You should also use this time to build up base defenses, so that you can keep the repeated later Terran strike forces out.