Frosty Depths

The Frosty Depths is the first cave you'll find in Pikmin: Connection of the Worlds and is found at the Snowy Mountain. It serves as the tutorial cave for the game, as it has only 3 floors, 5 Treasures, and easy enemies (only rivaled with the Peaceful Well, the single cave in the Garden). You also discover Purple Pikmin here.

Accessing the Frosty Depths
There's a cardboard box in front of an icy river that cuts through the land. It blocks a bridge that goes to an island in the river, and two more split off. Since you can only grow a maximum of 25 Pikmin the first day, you'll have to come back to grow more Pikmin. 40 or more can crush this box. Afterward, build the two bridges (there's really a third one; it's blocked by some ice) and continue forward. The snow-covered grass gets taller and taller, so watch out for some enemies that might surprise you! It gets so tall that it fills the camera, but then suddenly disappears. The hole is in view!

Wildlife
Snow Bulborb X13

Dwarf Red Bulborb X17

Red Bulborb X1

Sublevel 1
Your first level, it starts out simple: similar to that of the Emergence Cave from Pikmin 2. There are two small chambers joined together, and there are three Snow Bulborbs guarding a Treasure. If you collect the enemy carcasses back to the Research Pod, it will say how it loathes collecting those "disgusting, decaying bodies" (making a reference to Pikmin 2) but is willing to collect them, which trades them for Pokos. Get the Treasure and leave.

Sublevel 2
Now there are more Snow Bulborbs here. At least ten are scattered randomly around the level, which is made of two chambers again, but a series of passageways connect them. One of the Treasures is in a chamber, while the other is in an alcove. Find the hole, then go down it...

Sublevel 3
This level is quite big. A single tunnel leads down, down, down to a huge, yet warm room with three (yep, three of them) Violet Candypop Buds! And now... you have just found the Purple Pikmin! Two eggs also accompany this room, unfortunately, along with 7 Dwarf Red Bulborbs. Flower your Pikmin if you want, and/or kill the Dwarves. At the end of this chamber, there is a puzzle involving scales. They each need 60 Pikmin, but use your Purples, for you don't have a 120 Reds! Once they go down, another passageway leads to another chamber, but the tunnel itself is short. The final chamber houses the escape geyser, however, with a Red Bulborb and 10 Dwarf Red Bulborbs. The Red Bulborb holds a Treasure, while the other one is in plain sight. Once you have finished everything you feel you need to do, you can leave.