The Last Chaos Emerald!

Hiya! Well, this is not good, it looks like Metal Sonic has stolen the last Chaos Emerald from Sonic and Tails is in shock as well as Sonic points at Metal Sonic to give it back.. you can see Dr. Eggman is right in front of them to take it away and ready to go and head back to Dr. Eggmans Head Quarters! What will Sonic and Tails do now? Will they get it back or will they have to fight Metal Sonic to get their Chaos Emerald back!^^