The neon glow of New York flickered across the rooftops as the turtles huddled around Donatello’s latest invention, a cluster of mutagen sensors pulsing with a warning.

“Guys… this isn’t good,” Donatello muttered, eyes scanning the readouts. “The sensors just picked up a mutagen signature. It’s… very close, and… it’s definitely not one of us.” He adjusted his goggles, voice tight with excitement and unease.

Raphael’s eyes narrowed, muscles tensing instinctively. “Another turtle? Are you serious, Donnie? How the heck did we miss one?!” He slammed a fist into his palm, but there was a flicker of nervous curiosity behind his usual bravado.

Leonardo stepped forward, kusarigama ready, his calm leadership kicking in. “Relax, Raph. First, we need to find them. Nobody knows if they’re friend or foe yet. Donnie, lead the way—careful, though. We don’t want to spook them.”

Michelangelo bounced on his heels, grinning wildly. “Ooooh! Another turtle to hang with! Maybe they’re cool, maybe they’re a pizza-lover like me. I call dibs on introducing myself first!”

Donatello shook his head. “Wait, Mikey. We don’t even know if they’re safe. Mutagen can… twist people. I don’t want anyone getting hurt before we know what we’re dealing with.”

Raph crossed his arms, smirking slightly. “Yeah, yeah, smart guy. But if they try anything funny, they’re gonna regret it.”

Leonardo’s eyes scanned the rooftops and alleyways. “Stay sharp. Keep your distance until we get a better sense of who—or what—we’re dealing with. Splinter would want us to approach carefully.”

They crept through the city, shadows flickering across broken fire escapes and graffiti-tagged walls. Suddenly, a flicker of movement caught Mikey’s eye.

“Whoa! Did you guys see that?” Michelangelo whispered, eyes wide with excitement. “Someone’s… someone’s there!”

From the darkness, a figure hunched low, barely visible except for a pair of glowing eyes watching them intently. The new turtle’s presence radiated caution, their posture tense, ready to bolt or fight.