The book is dedicated to the glorious combat past of engineering units, in which four-legged soldiers served side by side with people on the fronts of the Great Patriotic War, and is written on the basis of authentic material (conversations with the characters of the book, archival documents - orders, instructions, combat reports of 1924 -1945, many of which have recently been declassified and published for the first time). The work tells the story of the 37th separate engineering battalion of tank and mine-detector dogs and the 5th Guards engineering brigade of front-line subordination, created by the legendary I. G. Starinov (Kalinin Front , 1st Baltic). In the 37th OBSM, for the first time in world practice (along with the mine-detecting service and reconnaissance service), dogs of the “D” service were trained - saboteurs capable of independently completing the task and returning to the counselor. The plot of the book is centered on the biography of the only female officer of this service, the platoon commander of the 37th OBSM, who trained the dogs of the “D” service, who were to fly behind enemy lines to participate together with the Belarusian partisans in the “Rail War” program.