Flashback Agent G.U.N SonAmy
Amy has just given birth to a cute hedgehog boy about a few hours ago, she looked at him and smiled. Sonic was sitting next to her.
Sonic plays with the baby with his finger, he giggled a little.
"What should we call him Ames? Sonic Junior?" Sonic asked Amy who held the baby.
"I like Navy" Amy said calmly. The baby at the same time was playing with Sonic's fingers. Sonic was unsure of the name but agreed.
"Navy? Yes it could work. We'll call him Navy" Sonic said.
"Very well. Navy, wanna go to daddy?" Amy asked Navy. Navy giggled and smiles as he was handed over to Sonic. Sonic rocking his newborn son in his arms. He couldn't help but sigh sweetly to that he's a father finally.
End Flashback
The next day when they can leave the hospital, both Sonic and Amy are not feeling well, so the both have to stay in the hospital, and Shadow has to take Navy home and take care of him. The doctor diagnose that they have an unknown virus. "I can't go on like this," Sonic groaned in pain.
Five Years Later
Navy the Hedgehog was a blooming hedgehog, blue-haired teal-eyed, and can summon a hammer and run at super speed. He was living with Sally Acorn. Why? Because five years earlier, Sonic and Amy are kidnapped by Robotnik, perhaps never to be seen ever again! BY ANYONE. And Sally had to confess to tell everyone her secret: she accidentally told Scourge The Hedgehog about the wedding but did not invited him. So he infected Amy and Sonic with a virus of his own design, rendering them both sick and powerless. That way , Robotnik will kidnap them both. As punishment upon finding this out, G.U.N ordered Sally to care for Navy. Luckily, Nebula The Hedgehog been married to Shadow, so she figured she could help.

"Aunt Sally?" Navy said searching for Sally. He found her in her bedroom, sitting on the bed. Navy then asked G.U.N to train him. Reluctantly, they said "Yes, but it'll take a while." Navy trained real hard. He bashed some practice robots, learned how to build something and run at his top speed. After about ten years of training, Navy becomes tech-savvy Agent N. The General tells "Okay, Agent N, here's your first assignment: you remember your parents being kidnapped by Robotnik after Scourge got them sick?"

"Yes, sir," Agent N.

"Well, your job is to go to Robotnik's base to get them back. Think you are up for it?"

"Yeah! In fact, that's what I will do."

Agent N presses a button on the strap of his new gold backpack. Spidery legs sprout out from the backpack and carry him off.