The Detective Case Files are special side quests in Fallout 4 carried alongside Nick Valentine. These quests have you solving a few investigations alongside our helpful companion.
Fallout 4 The Detective Case Files Side Quest
When in Diamond City, head into the Valentine Detective Agency and chat with Ellie the assistant (this must be done after you have found Nick). She’s come across some unsolved case files that you might be interested in solving.
You’ll acquire the Earl Sterling Case File and the Marty Bullfinch’s Holotape. Picking up the former will start the side quest ‘The Disappearing Act’, while listening to the latter will start ‘The Gilded Grasshopper.’
We’re going to start off with The Disappearing Act first.
Detective Case Files: The Disappearing Act
Earl Sterling was a bartender at the Dugout Inn. You need to get into Earl’s house and search for some clues.
You can pick the Novice lock on Sterling’s house in Diamond City, or you can talk to Vadim Bobrov in the Dougout Inn as ask for the key. You can also talk to Yefim in the inn and inquire about Earl Sterling.
Once you’re done, enter Sterling’s house. If you’ve brought Nick along with you, he’ll help in discovering some clues.
Check under the couch here to find something of interest. These clues will lead you to the facial reconstruction specialist in the Diamond City market. Head over there and speak to Doctor Sun about him.
Inspect the marks leading to the surgery cellar, and about them. If you have high Charisma, there’s a chance you might be able to successfully demand an explanation regarding the marks.
You’ll need to either pick the Advanced lock to the surgery cellar, or persuade Doctor Sun into opening it by either threatening or mentioning your investigation. You can also bribe him for 100 Caps if you wish.
Eventually, you’ll make a case-solving discovery in the cellar. Speak to your suspect. You can either arrest him, end the standoff peacefully, or simply kill him. After the chat with Doctor Sun, return to Ellie and collect your reward of 200 Bottlecaps.
Detective Case Files: The Gilded Grasshopper
Listen to the holotape Ellie gave you. According to the tape, Nick’s former partner Marty believes there’s a treasure map hidden in the Gilded Grasshopper on top of the Faneuil Hall. Head to hall and go through the enemies you find.
You’ll need to ascend all the way to the rooftop. Look for a ladder to the roof as you go through the structure’s interior. Be sure to grab the Live & Love magazine in this building, along with a Fusion Core.
Once you’re on the roof, locate the Guilded Grasshopper and read the note inside. The note seems to point towards Shem Drowne’s grave. It’s located in a cemetery between Cabot House and Pickman Galley in North End Neighborhood.
Take out the Feral Ghouls here and inspect the grave. You’ll find a note, some copper, silver, and gold bars, and Shem Drowne’s unique Sword.
Enjoy the spoils!
Detective Case Files: Long Time Coming
Once the two previous cases are closed, you’ll gain affinity with Nick. Talk to him and he’ll speak to you about a cold case. Talk to both Nick and Ellie to initiate this quest.
Nick requests for your help in recovering 10 Holotapes belonging to Eddie Winter. He believes the Commonwealth’s police evidence terminals should give a clue to the location of these tapes. Nick will give you the first, but you’ll have to find the rest.
Read the Eddie Winter Case Notes, then look at the world map for the locations of the tapes.
You’ll need to fulfill the chore-like task of visiting each location. At each one, there’s a police evidence terminal on which you can access the file on Eddie Winter. Once you do, you can search the building for the holotape.
- BADTFL Regional Office – There are raiders here. The tape is on a filing cabinet. You’ll also find a copy of Guns and Bullets magazine while you’re here.
- Malden Center Police Station – The unmarked location near the Malden Center has a desk inside with the tape on it. You’ll also find a Fatman and Tumblers Today magazine here.
- Quincy Police Station – Beware of the Gunners here – especially Tessa, their leader who is in a Power Armor. The tape is nearby a locker.
- Natick Police Department – There’s a tape inside the evidence locker, but this place is guarded by a Deathclaw. Better get your Power Armor ready for this one.
- Nahant Sheriff’s Department – The tape is on a filing cabinet here.
- East Boston Police Station – The wrecked police station has a tape on a desk.
- South Boston Police Department. There are some pretty mean Mongrels here, as well as a Police Protectron. Take them out, then find the tape on an office desk.
- Police Precinct 8 – This place is west of Boston Public Library. You’ll find the tape in a nearby cell.
- Coast Guard Pier – There are plenty of Super Mutants (and Mutant Hounds) here, so be careful. The tape is on a safe. You’ll also find the Astoundingly Awesome Tales 2 magazine here, along with a Mini Nuke.
Once you’ve found all these holotapes, turn them over to Nick. He’ll decipher the tapes to find the code to Eddie Winter’s bunker. Now, it’s time to go to Andrew Station and put an end to Eddie.
There are plenty of raiders here. Descend into the subway tunnels and sewers. Look for a metal door with a keypad. Simply input the code Nick deciphered to get inside.
Once inside, it’s time to take care of Eddie Winter. Once you’ve taken care of him, be sure to pick up his unique revolver. Afterward, Nick has one more matter to deal with. Exit via the ladder and head to Joe’s Spuckies Coffee Shop. Talk to Nick here when he finds the location he’s looking for.
You’ll now be able to reach the highest affinity with Nick, after which you receive the Close to Metal Perk.