The story so far: Sonic & Tails got passed Bean & Bark, all the while Robotnik's spies have been watching
Tails was a bit shaky after the duel with Bean and Bark, Sonic, on the other hand, was calm, and eager to get to the Floating Island. They got there a few minutes after there scrap, and landed the Tornado in an open area several yards inland of the Island. The pair raced to the emerald chamber, casually jumping pits, and dodging the odd trap as if it was a walk in the park. Within moments they had reached the emerald chamber, and the moment they had, Knuckles had his paw around Sonic's throat.
"Where's the Emerald?" yelled Knuckles, squeezing Sonic's throat hard enough for Sonic to begin gasping for air. "Hand it over right now, and I'll let you walk away unscathed."
Tails couldn't stand to see this, Sonic was his best friend, and Knuckles was trying to kill him. Without giving it any thought, Tails leapt onto Knuckles. "Get off of him!" he yelled, before Knuckles threw him off. This was enough of a distraction Sonic needed, and without a moments hesitation Sonic curled up into a ball, sending Knuckles flying towards the emeralds. With a spin dash, Sonic quickly rolled towards Knuckles. Knuckles jumped to the right, and watched, as Sonic smashed into one of the emerald pedestals. Realising what he had done, Sonic jumped into the air and grabbed the dark blue emerald that had become dislodged.
Knuckles eyes lit up with rage. "Put that emerald down now, you thief." he'd already lost one Emerald, to who he didn't know, but Sonic's actions made him believe it had been Sonic all along. After all, who else could circumnavigate all the Floating Islands traps, other than Sonic. Knuckles lunged at Sonic, knocking him backwards. Sonic tried to fight back, but Knuckles would not relent. Acting on impulse, Sonic threw the Emerald at Tail. Tails caught it, slightly surprised. Knuckles began to charge directly at Tails, fists first. In shock, Tails threw the emerald back, just as Sonic had hoped. Sonic caught it, and ran at Knuckles, hitting him with a spin dash that sent him flying forwards. Tails leapt out of the way just in time to avoid a collision.
"I don't have any of the emeralds Knucklehead" Sonic said, before adding, "well aside from this one" Sonic grinned as he showed off the Blue Emerald he still held. Knuckles got up again, and jumped at Sonic. Sonic bounced back, landed, and then jumped, curling into a ball as he did, and hit Knuckles with a spin dash. The echidna was knocked down, and lay on the ground for a few moments.
"He's telling the truth." Tails yelped. "We only came here because Sonic heard a voice while under the Floating Island last night, and he wanted to know if everything was okay." Tails' voice was ignored, and Knuckles responded with a spin dash that sent Sonic flying. Sonic got up, and ducked a punch from Knuckles that knocked part of the wall away. There was some sort of chamber in there.
"Did you think to look in there for your missing emerald?" Sonic teased. Knuckles continued to swipe at Sonic, fuelled by rage. Sonic continued to duck, and after a couple of punches, Sonic was able to retreat back into the chamber. Knuckles ran after Sonic, with Tails following closely behind. Knuckles glided straight into Sonic, knocking him flying. Sonic rubbed his face; that last collision had hurt. Knuckles made another glide for Sonic. The exact moment before Knuckles hit Sonic; however, Sonic curled up into a ball, and started revving. Knuckles was sent flying into some ancient machinery. A bright light flickered where Sonic was stood, and Sonic began to disappear, still holding the Blue Emerald. Tails and Knuckles both watched as Sonic's body faded out of sight.
The light which had caused Sonic to disappear was still there, Knuckles jumped into it, eager to get back his Chaos Emeralds, with Tails following closely behind, following Sonic as always. The pair disappeared like Sonic had, and re-emerged on a set of old ruins. Knuckles recognised the place as the Sky Sanctuary Zone. "Where are you Sonic? Hand over the emerald now!" Knuckles ordered. They was a silence. For a few moments there was no noise except for that of the wind. Tails yelled out for Sonic, there was still no response. Tails looked to his left and saw the Floating Island; they were a good few miles from it.
"This place can't rise can it?" Tails asked Knuckles slightly nervously.
"No, why should it?" Knuckles responded, not exactly sure what the orange fox was getting at. "This place only stays afloat thanks to leftover Chaos energy from centuries ago. There is no steering mechanism like there is on the Floating Island."
"But this place is stable in altitude, right?" continued Tails, trying to satisfy his curiosity.
"Pretty much so" answered the red echidna, his dreadlocks flapping about gently with the wind.
"Then the Floating Island is sinking!" yelped Tails, finally making his point understood to Knuckles. Knuckles starred in disbelief, as the island began to sink in front of his eyes. Without at least one of the two missing emeralds he had no way of keeping the island in the sky, yet if the island were to crash the rest of the emeralds, would be scattered, and he would be stranded here in the Sky Sanctuary Zone. The drop was too much for him to glide down, and there was no way Tails could stay in flight that long. Of course, if he returned to the Island, and landed it safely, he would lose Sonic, and potentially the blue emerald. Knuckles had to make a decision as to what he was going to do.
What will Knuckles do? Where is Sonic? There's only one way to find out, keep reading