Nobody, she said to herself, is necessarily what he appears to be; nobody.

On an ordinary train journey to Scotland, Sheila Grant becomes embroiled in a plot that is anything but: a chemist has gone missing, an artist has been kidnapped, and a poet has been murdered.

As Sheila begins to understand the enormity of the situation, she realizes her life is in grave danger and must flee across the Scottish Highlands in search of assistance and a man named Appleby.

In London, Appleby is trying to piece together a kidnapping, a death, and a disappearance as the world wavers on the brink of another war. He has no idea he is Sheila’s best hope of survival.

When the clock is ticking and no one is quite who they claim to be… will Appleby find Sheila before it’s too late?

The Secret Vanguard was originally published in 1940.