Death Riddle

In a case out of the blue, private detective Plato Cartessis, assisted by the police, tries to solve a riddle of four words, unrelated to each other, whispered to him by a man breathing his last at his doorstep, literally in his arms, with four bullets in the back, unaware that the people behind the murder would stop at nothing in order to accomplish their final goal. Once more, he has to place his life at stake and this time all the odds are against him!