Having Maurizio Merli on your tail must be like having a pack of hounds chasing after you (or Pepe Le Pieu, if you want a less scary comparison). The perp in question here isn't even on the same continent - he's high tailed it to New York, and Merli still wants to track him down.
That said, you can just jump on the next plane to the Big Apple without some sort of evidence. The gangster who fled is a mob boss wanted for ordering the murder of two other mob bosses in Palermo, and the cops in NYC have been tipped off that he's there, which makes him go on the run. Meanwhile, back in Italy, Merli and partner Venantino Venantini are trying to clean up the mess while various witnesses are bumped off by the Mafia. During a hit, Merli (well Venantino really) capture a button man alive, but the guy won't talk...until he finds out the mob boss has killed his sister.
The main bulk of the film details Merli trying to get this witness to New York without him being killed by the masses of mobsters armed to the teeth, which makes for steamlined, tension filled plot as anyone they encounter could be a hitman, and mostly are! Merli punches, shoots, ducks, runs, scampers and growls through the entire film, even taking on a gang on New York street punks. I don't have a single complaint to make about this film!
There's never a dull moment in this one, right up to the last second.
We're also beginning to see a gradual shift of setting here as half of this is filmed in New York, soon to be a trend as we'll get to see The Bronx Warriors, 2019: After The Fall Of New York, Escape from The Bronx, the New York Ripper, Zombie Holocaust, Inferno, Manhattan Baby all taking place in New York city. Maybe the Italians just liked it there. Who knows?