Hah! Still seemingly not missing anything by skipping Part I of this book. In fact, they've all been referring to the last book of this series as if it just happened and ignoring the whole shipwrecked-in-Japan-with-amnesia subplot.
They are gearing up to leave China to return to Britain and the war. Laurence *groan oh of all the over-used truly bad plot points* has
recovered his memory after a battle where he received a head injury