The Break of Dawn

Walkthrough
This quest can either start when you find Meridia's Beacon in some random chest, or when you first approach the Statue to Meridia near Solitude.

Bring Meridia's beacon to Mount Kilreath
If you do not already have the beacon, Meridia calls upon you to find Meridia's Beacon and bring it back to her shrine. The location of the beacon is random and changes with every game. It is always in a treasure chest.

Replace the beacon
Once the beacon has been obtained, place it at the feet of the Statue to Meridia.

Guide Meridia's Light through the temple
After replacing the beacon, the Dragonborn is teleported high into the sky, where Meridia speaks of a Necromancer, Malkoran, who has defiled her temple, located beneath the Shrine, and must be destroyed. At this point, the doors of the ruins and temple are unlocked.

Inside the temple are a large number of "desecrated corpses" (×42) which each contain an unusually large amount of gold (20–125, levelled) and the ruins are guarded by Corrupted Shades (×21).

To make it through the ruins, the Dragonborn must activate pedestals to direct Meridia's beacon of light, creating a continuous path of light.

Destroy Malkoran
After killing Malkoran, there is an altar with the sword Dawnbreaker at the rear of the chamber.

Retrieve Dawnbreaker
Retrieve the sword from the altar. Again the Dragonborn is transported high into the sky above the statue, above Skyrim. Meridia then gives you this sword as a gift and tells you to wield it in her name. The Dragonborn can choose to let someone else use the sword, but that does not matter to Merdia.