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Sarah Kerrigan assaulted the protoss world of Shakuras and abducted Matriarch Raszagal. Kerrigan was confident that with Raszagal in her control, she could assault the Second Overmind with impunity.
Her judgment was shortly proven correct: a protoss carrier commanded by Dark Prelate Zeratul hailed Kerrigan, demanding an explanation for Raszagal's abduction. Kerrigan explained she had taken Raszagal just to get to Zeratul, and blackmailed him into aiding her; Kerrigan needed Zeratul and his brethren, as only dark templar could kill the Overmind for her. If Zeratul did this, Kerrigan vowed Raszagal would be freed. Though Zeratul was dubious of her words, Raszagal told him he must aid Kerrigan, as the Overmind was their common enemy that should be destroyed for the good of all. Zeratul reluctantly agreed.
Kerrigan engaged the United Earth Directorate with her broods and a small number of dark templar that were part of Zeratul's warband. They assaulted the Overmind's plateau and weakened the creature, sending it into a cocoon state. Zeratul arrived and personally finished it off. With the Overmind dead, Kerrigan arrived on the scene with Raszagal, and Zeratul demanded her release. Kerrigan allowed Raszagal to leave, but Raszagal pledged her obedience to Kerrigan. Zeratul was infuriated to learn Kerrigan had somehow corrupted Raszagal's mind, and Kerrigan boasted she had been manipulating Raszagal since before she contacted the protoss in person on Shakuras, and through her has used Zeratul to kill her enemies.
The first priority in this mission is to strengthen the player's economy, as they begin with few resources and drones. A small resource node is on a cliff overlooking their base to the west, and should be seized early on as it is very secure against enemy attacks. The provided protoss structures allows the training of up to eight dark templar, and they make valuable defenders due to their innate cloaking and powerful attacks. The player must have access to dark templar at all times or the mission is lost; if the protoss buildings are destroyed, the remaining dark templar can still kill the Overmind, but their deaths result in defeat. For this reason the protoss buildings should be fiercely defended, and at least one dark templar safe in reserve, just in case.
This map has a unique mechanic in regards to the enemy forces. While there are technically only two enemies forces, the UED and their slave brood, both forces have access to both terran and zerg units and structures. This means the player is effectively fighting two enemy forces that themselves each has the strength of two enemy forces. The enemy will combine their units liberally, and have access to the entire tech tree of both. Late in the mission, they will send out a massive air force of mixed units; wraiths, mutalisks, valkyries, devourers, guardians, and potentially battlecruisers. Defilers are a must to survive this attack, without them this attack will likely end the mission in the player's defeat.
There is a light orange base to the east and a white base to the north, both should be destroyed as early as possible; hydralisk, mutalisks, and guardians make a potent attack force. Overlords with their speed and vision upgrade should be brought along to spot enemy lurkers. With these bases gone the player can focus on fortifying their air defenses, as the rest of the map is not accessible by land and so all subsequent attacks will come in the form of air units or transport drops. The two destroyed bases can be expanded into, and another large mineral field is south-east of the orange base.
There is a large white base in the middle of the map inaccessible by ground. A large force of guardians can destroy it, but they will need mutalisk support to defend them from aerial retaliation that is sure to come. This white base is situated at a very large resource node that should certainly be taken. A nydus canal should be used to link the location to the main bases as a more convenient way to transport units from the site than overlords. The destruction of this base means the white force will no longer be able to mutate zerg units, though they maintain a terran base at the Overmind's plateau and so will continue to be a threat.
With their aerial army fully upgraded and as large as it can be, the player can now press their attack to the Overmind's plateau, moving out to the east of their new base. The orange base is to the south-west of the site, and it can be attacked or not; if so, there are defilers in the base who will use dark swarm when attacked. Once the swarm reaches the Overmind's plateau and clears it of defenders, an overlord with dark templar can move in an deploy them to kill the Overmind and win the mission.
If ground units are preferred to air, ultralisks are a must due to the enemy's usage of dark swarm. A resource node in the far south-east corner of the map can be seized and nydus canals used to move the player's ground forces here. With ultralisks leading the charge and dark swarm of either the player's or enemy's defilers to protect them, they can attack to the orange base and obliterate it, giving the player a staging ground to advance onto the Overmind's plateau. A second nydus canal should be placed at the orange base once the player expands there, allowing their reinforcements to get to the battle quicker than using the earlier southern canal.