This was a charming early Hitchcock comedy about a woman (Margaret Lockwood) who gets hit on the head and is cared for by an elderly Englishwoman (Dame May Witty), who mysteriously vanishes on a train. It was, in fact, his last British film before heading to America and Hollywood.
After she vanishes, everyone denies ever seeing her. Only Michael Redgrave comes to her aid and helps her search for the woman. The comedy part of the movie is over, and now we change to a thriller. Their search uncovers a conspiracy as the woman has some valuable information.
The final part of the film is something of an action film as there is a big shootout and an escape by train. We have a little North by Northwest, and The General in the film, as well as The 39 Steps.
It was all good fun.