The Silent Barrier is a story of mystery and romance with Charles K. Spencer, a well-to-do young American mining engineer, as main character. Drinking his water in a hotel in London one day, he overhears a conversation between two young women, one of whom speaks of going to Switzerland. He decides to play "fairy godfather" and send the comparatively poor, but most amicable other girl there, without her knowing anything of him, under the pretext of furthering her career as a writer for a scientific journal. However, the girl is shadowed on her journey by the mysterious Mr. Mark Bower. Convinced from the first that Bower is a rogue, Mr. Spencer decides to follow them to protect the girl...