Final Fantasy 7 Side Quest - Kalm Traveler
The town of Kalm is adjacent to Midgar. Later on in the game, right around the middle to end of Disc 2
or anytime in Disc 3, visit Kalm's rightmost building. Inside, you'll find a man who seems
quite happy the way everything is. This changes when Meteor is summoned and the WEAPONs begin
attacking. When this all happens, he'll begin to search for the Guide Book, Earth Harp, and
Desert Rose. If you bring any of these three items, you'll receive QUITE worthy prizes.
To get the Guide Book, you'll need to salvage the Underwater Reactor. Before this, make sure
you have the Morph materia, as the Guide Book is not found in a typical treasure chest. When
in the Underwater Reactor, find the enemy 'Ghost Ship' and use Morph on it. It can be found
usually around the tunnels along the ocean floor. If you take this item back to the Kalm
Traveler, he'll give you the Underwater Materia, used during the fight with one of the two
American WEAPONs, Emerald WEAPON.
If you defeat both American WEAPONs (Emerald and Ruby), you'll receive the Earth Harp from
Emerald and the Desert Rose from Ruby Weapon. Go back to the Kalm Traveler with these items,
and in exchange for the Earth Harp you'll receive the Master Summon, Master Magic, and Master
Command Materia. If you give him the Desert Rose, you will receive a Gold Chocobo.