Ideas:Mission/Mission 2 - A Piece to the Puzzle

After discovering the Red Gem at the Cave, G had said to show it to Sensei at the Dojo. G also said that Sensei may have more Info about it. Your assignment is to find out what the Two Gems are for and where to find them. Medal: The Truth Finder Medal
 * Enter the Dojo from the Dojo Courtyard.
 * Talk to Sensei.
 * Sensei: "Ah! Agent! Glad to see you. What can Sensei do for you?"
 * You: "I found another one of those Gems yesterday, I came to show it you."
 * Sensei: "Another Gem? Let me see it, Please."
 * Give Sensei the Red Gem.
 * Sensei: "You found a pretty rare Gem, I say. There's so much background Info about it."
 * You: "What do you mean, Background Info?"
 * Sensei: "This is going to be a bit Difficult to Understand, but you'll get the hang of it."
 * Sensei: "Long ago, Before you first Saw me, I was a native to the Island. I was secretly located in the Wilderness, where I met the Fluffy Creatures of this Island, Or Puffles as we call them. I was walking through the Wilderness one day when I found a Pendant. It was Gold, and had symbols on it showing Fire, Water, and Snow. In the Middle, there was a Black Gem. It meant the Ninja Element. So in my Cave deep within the Wilderness' Forest, I got to work on this 'Amulet'. I scraped out three different Coloured Element Gems. A Blue one for Water, a Red one for Fire, and a White one for Snow. I put these Gems onto the Amulet and It showed me The Future. Fire Ninjas, Water Ninjas, And Snow Ninjas, all standing together, as the Masters of the elements. So I shattered the Amulet Gems, and hid them across the Island. But I kept the Frame for the Amulet with me. Then, I gave that Amulet Frame to you."
 * You: "So, what you're saying is, I'm wearing a real rare Amulet?"
 * Sensei: "That's It in a nutshell, Yes."
 * You: "If I'm going to fill this Amulet up with the Element Gems, Should I put on the two gems?"
 * Sensei: "Why not? Have a go!"
 * Take the Two Gems off Sensei and put them with Your Amulet.
 * Place the Two Gems in the right place. The Black one in the Middle, and the Red one on the Fire Symbol.
 * Sensei: "There we are! You are so close to filling all the Amulet."
 * You: "Where can I find The others?"
 * Sensei: "Oh, I can't tell you. You'll have to find that out for yourself!"
 * You: "Thanks for your Help!"
 * Sensei: "Anytime!"
 * Go to the Gadget Room and Talk to G.
 * G: "Agent! You're back! I need your help!"
 * You: "What is it, G?"
 * G: "I need your help on placing the parts on my new Invention! Can you do this?"
 * Accept G's task.
 * Use your Wrench to put the Parts to the Invention in the Right Place.
 * G: "There we are! One Electro-Excavator 3,000 ready for Using!"
 * You: "What's one of them, G?"
 * G: "Ah! You'll be using this in your Next Mission! Farewell agent!"
 * The Mission will End.

Prize: A letter from Sensei.