Abandon Thyself by Sanjuno - Code Geass Fanfiction on AO3
I really enjoyed the characterization of the Suzaku and Lelouch here, and especially their interactions. While I did find the Suzaku a bit out of character, it was still believable enough and it made for a really interesting read. It was this characterization, that gave this entire story its very, very interesting atmosphere. Suzaku's inner dialog was great - and seeing his in the planing position really underscored his and Lelouch's differences.
Lelouch's reactions to the entire situation were spot on. Let it be bleeding of his different characters together, trying to put the people around him first, or even him just quickly adapting to the situation. For all Suzaku's knowledge of the future and Lelouch, he still got surprised on the end.