How to Replenish Water

Homare finds the solitary island where Shion washed ashore and the two are reunited. But there`s no time to rejoice. With no food or water, succumbing to dehydration is only a matter of time... All they have is filthy water they find in a cave... In this dire situation, the two of them use a secret technique for rehydration!? Will Homare and Shion make it back to the island?