Kingdom Hearts: Chain of Memories

From Yen Press:

“Ahead lies what you seek…but to claim it you must lose something dear.” When a mysterious hooded stranger confronts Sora, Donald, and Goofy with these words, leading them to an ominous castle, the trio is sure they’ve stumbled onto an important clue about rescuing Riku and King Mickey after they were trapped in the darkness. But what looms ahead is Castle Oblivion, and to walk through its doors is to pay a heavy price. What are Sora, Donald, and Goofy willing to give up to be reunited with their friends?