You Only Live Twice is the 12th book in the James Bond Original Series by Ian Fleming.
The tragic end to James Bond’s last mission―courtesy of Ernst Stavro Blofeld―has left 007 a broken man and of little use to the British Secret Service. At his wit’s end, M decides that the only way to snap his best agent out of his torpor is to send him on an impossible diplomatic mission to Japan. Bond’s contact there is the formidable Japanese spymaster Tiger Tanaka, who agrees to do business with the West if Bond will assassinate one of his enemies: a mysterious Swiss botanist named Dr. Guntram Shatterhand.
Shatterhand is not who he seems, however, and his impregnable fortress―known to the locals as the “Castle of Death”―is a gauntlet of traps no gaijin has ever penetrated. But through rigorous ninja training, and with some help from the beautiful and able Kissy Suzuki, Bond manages to gain access to Shatterhand’s lair. Inside lurks certain doom at the hands of 007’s bitterest foe―or a final chance to exact ultimate vengeance.