Whereabouts of the Grail

What are you doing here? Looking for Holy Cup? I guess I got Holy Cup from bottom of the sea. A few days ago, I picked up a gold glass. It looked miraculous.

I can't give it to you if you need it. But would you do me a favor?

I explored the sea for a long time and my equipment is all broken. To fix it. I have to go to Aquarium but don't have enough time. So I'm thinking of using a sturdy Shark Denture to fix everything. Can you get 10 Shark Denture from Shark?

It was tough to pull it up. It's worth it.

Finally, you came back. Thank you. This is what I picked up from the sea. Is this what you're looking for?

Good. I don't know where you're going to use it. It's valuable. Please keep it safe!

Where is 10 Shark Denture?