Juvenile series, dark & brooding. Boy in dungeon-like chamber peers into a hole in the floor and escapes through it. Read 1980-1985.

[David]

Kind of a dark, brooding juvenile fiction series. Joan Aiken-style, maybe.

I remember a scene where an adolescent boy is in a dungeon-like chamber peering down into a hole in the floor, probably a drain. He either just finished or is about to use the drain system to sneak in or out of the dungeon, which is probably part of a castle.

Kind of a LadyHawke vibe with the sneaking in the sewers.

I read the book between 1980 and 1985.

Thanks in advance.

[Lobstergirl, au gratin]

To avoid confusion, you originally created a thread for this here:

https://www.goodreads.com/topic/show/...

but were searching for two books in that thread so Kris asked you to create a separate request. This is not a duplicate thread.

[Orsolya Könyvtáros (formerly Memp)]

The Black Arrow has a scene where the main character (teen boy) is being held captive in a castle and escapes through a trap door in the floor. There are various peep-holes in the escape passage through which he can see other parts of the castle. The boy is able to swim across the moat and escape.