El comisario detective Belli (Franco Nero) comienza a investigar un caso para un amigo, el de un asesinato cuyas pistas pasan por la bella modelo (Florinda Bolkan) de un escultor, y comienza a verse envuelto en una trama de asesinatos, engaños y traiciones.
The World of the Blues (Main Titles) — Fred Bongusto
Un detective (Love Theme) — Fred Bongusto
Un detective (Mystery Version) — Fred Bongusto
Un detective (Mystery Version 2) — Fred Bongusto
The World of the Blues (Waltz Version) — Fred Bongusto
Un detective (The Murderer Theme) — Fred Bongusto
Un detective (Love Theme 2) — Fred Bongusto
Un detective (Mystery Version 3) — Fred Bongusto
The World of the Blues (Waltz Version 2) — Fred Bongusto
Un detective (Piano Solo) — Fred Bongusto
Un detective (Mystery Version 4) — Fred Bongusto
Un detective (Party Music) — Fred Bongusto
The World of the Blues (Piano Solo) — Fred Bongusto
Un detective (Love Theme 4) — Fred Bongusto
Un detective (The Murderer Theme 2) — Fred Bongusto
The World of the Blues (Theme Song - Alternate) — Fred Bongusto
The World of the Blues (Off Vocal Version) — Fred Bongusto
The World of the Blues — Fred Bongusto
The World of the Blues (Theme Song) — Fred Bongusto
Un detective (Love Theme 3) — Fred Bongusto