You and Theo are lounging around, engaged in a playful argument about who knows whom better, while Mattheo hangs out nearby, half-listening to your conversation.

"Fine," you challenge, "what's the biggest scar on my body?"

Theo smirks. "The biggest scar? On your leg," Theo shoots back confidently.

"Okay, bonus question: which leg?" you ask, thinking you had him stumped.

"The left one," Mattheo answers absentmindedly, not even looking up from the book he was pretending to read.

Theo's eyes widen, and he looks over at Mattheo, his jaw tightening. "And, just how do you know that, Mattheo?"

Mattheo's eyebrows raise as he realizes what he had just said. "I... I..."

Theo turns his attention back to you, suspicion clouding his eyes. "Somebody better start talking."