The Glowing Sea

The Glowing Sea is a main story quest in Fallout 4.

Detailed walkthrough
Kellogg's memories and Doctor Amari's advice indicate that the player should locate an escaped Institute scientist, Virgil. His last known position was deep in the most irradiated region of the Commonwealth, the Glowing Sea.

Commence the long trek southwest, following the remains of the freeway until your Pip-Boy indicates a hike off-road is in order. Expect to face deathclaws, radscorpions, feral ghouls, and other irradiated wildlife. When reaching the map marker, the player character is close to the Crater of Atom.

When entering the location of a strange cult, led by Mother Isolde, the Sole Survivor is actually trespassing. Though violence is always an option (search the area for a scrap of paper indicating a nearby cave), one can lower their weapon and speak to Mother Isolde instead. Answer her politely. She will direct the Sole Survivor to a nearby cave.

Locate the rocky cave roughly southwest of the Crater of the Atom. Watch for, or sneak past, the roaming deathclaw.

The Sole Survivor will find Virgil inside this cave. He requests to help him locate a serum within the Institute in return for his knowledge.

When entering Rocky Cave be sure not to destroy any of Virgil's defenses. Any defenses destroyed prior to returning to complete the quest will result in failing the quest when returning with the serum. Virgil will immediately turn hostile when you return.

Bugs
Upon entering the cave Virgil isn't there. The marker for finding him points to the ground. This may be the result of having visited Virgil's cave prior to the quest.
 * On PC, using console command and then  may force Virgil to appear in the cave.

Mar Resplandeciente (Misión) Светящееся море (квест)