La città sulla cordigliera / Labirinto verde / Sulle rive del grande fiume

In the Brazilian forest, the Spirit-with-the-Hatchet will have to face the Jivaros, the head-cutters! 

Chico was kidnapped by the Jivaros, the head cutters Indians, and the Spirit-with-the-Hatchet, before being able to set him free, finds the reason for the hostility of the Natives: a group of explorers, led by geographer Dr. Darq and his right-hand man Santos, is trying to find the sources of the Amazon Rio. To find it, they abducted the old medicine man of the tribe. Darq wants to forcefully extract  valuable information about the way to the sources,but the old man, who consider sacred the place the White men want to reach, is unwilling to talk...

The adventure with the headhunters is over, but Zagor and Chico go searching for the Amazons, to enlist their help in their search for Dexter Green. While they reach the point where the two rivers meet, where they've been told in the Andes the warrior women live, the Spirit with the hatchet and his Mexican friend meet a botanist, Spruce, who's there  to study the Amazonic plant species. All of a sudden, an enemy they believed to be dead comes back to centerstage.

Tribute to Mister No throgh scenes in Amazons which reflects his covers.

More at http://dimeweb.blogspot.com/2012/10/da-mister-no-zagor-una-storia-da.html