- Varies depending on the location
This quest comes available once you have completed The Railroad radiant Quest Mercer Safehouse (Quest). Speak to the new agent, Caretaker who needs to help a tourist so he can help a Synth escape. Answer him with a countersign.
Travel to the location he gives you and get to the marked enemy, and kill them. Return to Caretaker for your reward of Stimpak 4x and Bottlecap 150x.