Cappy in a Haystack

Cappy in a Haystack is a quest in the Fallout 4 add-on Nuka-World.

Detailed walkthrough
Between The Parlor and Fizztop Grille, Sierra Petrovita is encountered talking to a raider. Intercepting the conversation reveals that she has come to find the reward for finding hidden Cappys throughout the park. Given that the reward was meeting the creator of Nuka-Cola, she figures that in his office might be the original recipe for the drink. She gives her sunglasses to you before leaving.

Once you get close enough to a marker, it disappears, encouraging the thorough search of an area.

One is west of the Fizztop Grille, on the large wall beside the restrooms building.

The first Cappy in Safari Adventure is through the hedge maze beneath the treehouse, against a wall on the eastern edge. Watch out for the Gatorclaws. The second is just outside the Primate house, on the back of the gorilla statue to the right of the door.

The Dry Rock Gulch section has two; The first is located on the back of a gravestone next to the Giddyup Kid protectron. Another is located within the Mad Mulligan's Minecart Coaster, on the wall of a little shack beside the waterfall.

In Galactic Zone, there are two. The first is at the entrance to the dead traders' camp around the back of Starport Nuka, next to the Employees Only sign. The second is up the ramp right next to the exit door of the Robco Battlezone. Turn right immediately at the top of the ramp, and the Cappy is on the wall near the trash bins.

There are two in the Kiddie Kingdom.

One is in the funhouse in the turntable room, second door on the right when entering from the topsyturvy room.

One is in the ruined clock tower looking to the west of the bridge leading over the moat into King Cola's Castle.