Kissanos river is coming from Kedros mountain, passing Spili and following the valley south of Mixorrouma and Frati, passing between Koules and Ksiron mountains and meets Megalopotamos south of Kourtaliotes Gorge and they find the sea by Preveli beach. Here is running water all the year around. Below Frati is a partly ruined mill near a bridge over the river. A little higher up are ruins of a kind of fort. Down from Kato Mixorrouma by another river brigde, a sign is telling us that trout fishing is prohibited.
It is nice to walk in this area. It is possible to take circular walks from Mixorouma through Ag. Pelagia, to Frati on a dirt road above the north end of the Kourtaliotes gorge or the paved road into Frati, down to the river and follow the southern side of the river until the next bridge and up to Kato Mixorrouma on the northern side.
The cache is a Lock&Lock box with pencil, logbook and some trading stuff. It is placed on the southern side of the chapel. The signals were bad here, so the coordinates are not accurate, so look at the spoiler
There is a nice parking area with running water, just after taking off the Rethymnon-Spili road signposted for Kato Mixorrouma in the southern end of the village