"Okay, everyone, let’s pick up the pace! You’re not here to nap!" shouted Jenna, her voice cutting through the thumping bass of the workout playlist. Sarah groaned, wiping sweat from her forehead as she tried to keep up with the burpees. "I hate you," she muttered under her breath, but Jenna caught it and grinned, her ponytail swinging like a weapon.

Sarah and Jenna had been friends since college, though their lives had taken wildly different paths. Jenna, with her toned arms and endless energy, had become a fitness instructor, while Sarah, still in her rumpled graphic tee and leggings, was here under duress. "You said this would be fun," Sarah panted, glaring at Jenna’s perfectly coordinated neon outfit. "I said it would be *good for you*," Jenna shot back, her smirk unwavering.

As the class moved into cooldown stretches, Sarah noticed a man in the corner who hadn’t been there at the start. He wasn’t following the routine—just standing still, watching. His eyes locked with hers, and she felt a chill despite the heat of the room. "Jenna," she whispered, "who’s that guy?" Jenna glanced over, her smile faltering for the first time. "I don’t know," she said quietly. "He wasn’t on the sign-in sheet."