One Piercing Note

Talk to Abbess Benita in the abbey, in the centre room north of the fountain.

The cells are in the southeast corner. Enter the westernmost one (Anna's cell).

Inspect the bed and window.

Go back northwest to the room west of Abbess Benita's office and inspect the beds in there for another cloth fragment.

Run directly south and inspect the body (the body is covered up in the bed in the southwesternmost room).

Question 5 people around the abbey.

Valerio - Musician outside the abbey (3 clues).

Sister Elena, north of the cabbages, in the kitchen (3 clues).

Sister Cecilia, in the east-central room, the chapel (3 clues).

Sister Catherina, in the chapel (2 clues).

Feet (Sister Debora, once she stands up), on the floor 3 of the clock tower on the northeast side, sticking out under the clock mechanism. Talk to her, then, operate the clock mechanism to show 12 o'clock. Afterwards, talk to her again (2 clues).

Return to Abbess Benita, select any suspect.

Climb down the stairs to the cellar in the room northeast of the chapel.

Investigate the bloodstains (1 clue) and body (5 clues).

Search the robe cabinet south of Sister Elena's body. (1 clue)

Return to Abbess Benita for a cell key.

Search the sack (singular, not the sacks) in the kitchen adjacent, east of Abbess Benita.

In the southeast corner of the building, enter the second cell from the east (Elena's cell) and inspect the bed.

Read the letters, talk to Valerio the musician about Sister Elena's death (1 clue).

Talk to Sister Cecilia in the chapel for a clue.

Return to Abbess Benita and blame anyone/nobody.

Talk to Sister Catherina, who is now dancing outside near Valerio.

Talk to Sister Catherina again. A cutscene begins.

Climb the nearby ladder (immediately south of the closed gate), operate the winch, then climb back down.

You do not need to do this step if you skip the cutscene.

Talk to Valerio near the dead body.

Talk to Abbess Benita.

Pick a cabbage and climb down the stairs to the cellar in the room northeast of the chapel.

Click move on the candelabrum near the eastern wall in the centre of the room north of the Reliquary, then use a cabbage on it (but don't eat it).

Search the robe cabinet, then use the robes on the cabbage-on-candelabrum.

Hide-in the cabinet. You may skip the cutscene.

Knock out the Killer, then chase after them around the abbey.

Talk to the killer at the top of the tower.

Climb down the stairs. You will get sent all the way down.

Climb up the stairs twice and operate the clock mechanism so that the minute hand points to 12.

Climb up the stairs and talk to the killer about the bell.

Talk to Sister Debora, she'll leave.

Talk to Sister Anna (the killer). You may skip the cutscene.

Talk to Abbess Benita.

Quest complete!