In the house of a poor landlady, her tenant, Mr. Tapley, a quiet, modest, harmless man, was brutally murdered in broad daylight. Small, frail, always wearing the same shabby clothes, Mr. Tapley was, however, surrounded by some kind of mystery. He had good manners, was well educated and, despite his pitiful appearance, clearly did not need money. What made him lead such a strange lifestyle and who needed his death? Inspector Ross and his smart, brave wife Lizzie are determined to unravel the mystery of Mr. Tapley and find his killer...