The Yellow Tube

First published in the UK magazine called The Royal Magazine #216, October 1916. Collected in Donovan of Whitehall.
"Hugh Donovan pits his brains against those of a woman. How he outwits her and her confederate - both spies of the German Government - forms the basis for [this] thrilling adventure." The game for Donovan was a clever one, one he had to undertake unofficially as his methods would never be sanctioned. It dealt with the woman's seduction of an old friend of Donovan, rising in the ranks of the Royal Navy.