During an undercover assignment as a photographer in London, D-Agency's Kaminaga is captured and interrogated by Howard Marks, a spymaster for British Intelligence Secret Service. Even after being injected with truth serum and told that he had been set up by a diplomat, Kaminaga makes a deal with Marks to send a telegram with Japanese keying styles. Kaminaga manages to escape captivity with the help of a sleeper agent within Marks' organization. By receiving Marks' intel in verbatim rather than with errors, D-Agency learns about Kaminaga's situation and ensures his escape. It is revealed that Lieutenant Yuuki contrived the entire situation in order to discover the diplomat's leak.