Duty or Dishonor

Duty or Dishonor is a quest in Fallout 4.

Quick walkthrough

 * 1) Speak to Knight Sergeant Gavil
 * 2) Search for evidence.
 * 3) Read Knight Lucia's log
 * 4) Confront Knight Lucia
 * 5) Shadow Initiate Clarke
 * 6) Find Initiate Clarke
 * 7) (Optional) Exterminate the Ghouls
 * 8) Confront Initiate Clarke
 * 9) Kill Initiate Clarke, or convince him to turn himself in (If you choose Method 2, don't kill the locked up Feral Ghouls Below the room.)
 * 10) Report to Lancer Captain Kells

Detailed walkthrough
Convincing Clarke to turn himself in grants a piece of armor upon quest completion (T-60C torso with 10% AP costs in VATS reduced). Despite the captain stating that a team was sent in to clear out the ghouls, the room at the bottom of the ruins remains closed with ghouls inside if you return after completing the quest. You can enter, kill, and loot to your heart's content after Clarke turns himself in.

Killing Clarke yields no armor or weapon rewards, just 100 caps.