The Secret of Cabot House

The Secret of Cabot House is a quest in Fallout 4.

Quick walkthrough

 * 1) Meet Jack outside of Parsons State Insane Asylum.
 * 2) Help Jack reach his office.
 * 3) Help Jack reach the basement.
 * 4) Stop the raiders from freeing Lorenzo Cabot.
 * 5) Kill or free Lorenzo Cabot.

Plan A: Putting Lorenzo to bed
 * 1) Talk to Jack Cabot
 * 2) Talk to Lorenzo Cabot
 * 3) Kill the Cabots
 * 4) Talk to Jack Cabot

Plan B: Waking Lorenzo up
 * 1) Miscellaneous: Talk to Jack Cabot about the artifact
 * 2) Return to the Cabot house
 * 3) Kill Lorenzo Cabot
 * 4) Talk to Lorenzo Cabot

Detailed walkthrough
When returning to the Cabot house after saving Jack's sister, the player character will get this mission assigned by Jack to help prevent raiders from freeing Lorenzo. Although one can actually fail in preventing the raiders from freeing Lorenzo, the Sole Survivor still has to kill them all once Lorenzo is released.