Ready Or Not! Here I Come! (三姉妹とかくれんぼ, San Shimai to Kakurenbo, lit. Hide and Seek with the Three Sisters) is an event in Tomba! 2: The Evil Swine Return.
Find the three girls hiding in Ranch Area.
Koma is hiding in the ice/water slide, Ima is in the hole in the wall (you will need to throw something in bottom hole, an enemy or a snowball, to make her come out of it), and Rioma is on the ledge near the Snow Firefly Nest. Each girl will give Tomba a Snow Firefly for finding her.