14

As the gate unlocks, you turn back to check on Dobby Fischer. He's shaking off the snow, looking a bit dazed but otherwise unharmed. You ask if he'd like to come with you, but he shakes his head in response. "It's you that has go on," he insists, "Not me, not Hermione, you!" You wonder who Hermione is, but nonetheless proceed to enter the gate.

After unlocking the gate, you're met by another chess-playing elf, David Snowell. He leads you into a hidden underground cabin, where you see a group of elves gathered. "We've got some explaining to do," David says as you enter. "We were behind the last two puzzles in the bell tower and the gate," he explains. "We rang the bell to draw you to the church, where we placed the book for you to find. Our plan was to meet you in the bell tower."

You look very confused, trying to piece together the events. David pauses, giving you a moment to process. "When Dobby Fischer started heading towards the church, we had to act fast. We couldn't risk him joining in, as chess isn't his strong suit. We had to leave the bell tower quickly, and regrettably, we had to tackle Dobby and lock the gate to keep him away, knowing only someone with your chess skills could open it."

You are overwhelmed, and demand explanation. "I know this is a lot to take in," David acknowledges. "Before we explain everything, we need to make sure you're ready for what's to come. The best way to do that is with another chess puzzle." He places a chessboard in front of you. "Solve this," he says, "and we'll know you're ready to join us in our mission."

This is a serieshelpmate (just like Day 6). Black plays 11 consecutive moves, without reply from White, after which White mates in one!

No intermediate checks are allowed, meaning that Black can only check on the 11th move. Here's a board editor with the position (not that this editor doesn't validate legal moves).

Give the whole series of moves.