Visions in the Fog

Visions in the Fog is a main quest in the Fallout 4 add-on Far Harbor.

Quick walkthrough
Talk to Rictor. Go to spring and drink from it. Follow shadow figure. Kill ghouls at destination. Pick up note on table inside the shrine then read the side of a locker. Open door with password and grab the idol. Go back to Rictor

Detailed walkthrough
The Sole Survivor goes to speak with Brian Richter outside of The Nucleus. He explains that to join the Children of Atom the player must drink water from the sacred spring. When they arrive and drink the water, the player is greeted by the Mother of the Fog, a ghostly, dark figure covered in black smoke. She leads the player to a special shrine, where they will find the Mother icon behind a security door. Taking this icon back to Richter will complete the quest.