How to unlock: automatically after the Special Delivery quest
- Talk to Edward
- Optional: Ask around the Third Rail about Emogene
- Find Emogene Cabot
- Return to Cabot House
- Talk to Jack
The quest is simple. After the conversation with Jack Cabot, you can quick travel to Charles View Amphitheater. You must find his sister Emogene.
You will obtain additional information in The Third Rail bar in Goodneighbor, after the conversation with Charlie the robot.
Once you reach the amphitheater, you will find Brother Thomas there. He will admit that he knows the girl and that he is holding her in a room. If you have high Charisma, you can force him to release her. However, you will need at least few points of that parameter even to bribe him (500 bottlecaps).
If none of the above options suits you, you can free the woman by opening an advanced lock, stealing the key from Thomas or causing some ruckus (you will be attacked by everyone once you open the door anyway). The girl will tell you that she will get to her home alone, so you can go straight to Jack Cabot for reward. Emogene will also tell you about the properties of the serum which you can give to her - but it will not impact the quest or your relations with the girl.
Quest rewards: experience, about 200 bottlecaps, The Secret of Cabot House quest