"Mommy, help me!" Little Sophie Carter's voice had gone hoarse. Her fists barely made a sound against the tinted window of the black Mercedes as the summer sun turned the locked car into an oven.

Sweat ran down her cheeks and soaked the collar of her pale yellow dress. Every breath came faster and shallower, and each scream sounded weaker than the one before it.

Only minutes earlier, her stepmother, Claudia, had stepped out of the car in red heels and walked toward the marble entryway.

She pressed the remote, heard the locks click, then looked back. Her eyes met Sophie's through the glass.

Claudia gave the smallest mocking smile—and walked inside. Someone watching from a distance might have called it a terrible mistake.

Sophie knew better. Claudia had seen her. She had heard her. She had left her there on purpose.

On the front porch, Elena, the maid, was carrying a basket of freshly folded linens when she heard a faint tapping sound.

At first she thought it was a branch moving in the wind. Then came another tap. Elena turned toward the driveway and froze.

Sophie's hands were pressed flat against the window. Her face was bright red, streaked with tears, and her mouth was moving even though Elena could barely hear her anymore.

"Miss Sophie!" The laundry basket dropped from Elena's arms. Towels and sheets spilled across the porch as she ran toward the Mercedes and yanked on the rear door handle.

Locked. She tried the front door. Then the other side. Nothing. Even standing outside, Elena could feel heat pouring off the glass.

"Don't give up, darling! I'll get you out!" She pounded on the window with both fists, then spun toward the mansion.

"Ma'am! The keys! Please!" No answer came from inside. Elena shouted again, louder this time, but the only response was Sophie's weakening sobs behind the glass.

She pulled at the handle until her fingers hurt. She struck the window again and again until her knuckles split, but the safety glass held.

Inside, Sophie slowly sagged sideways against the seat. Her small chest was still moving, but barely.

Elena's panic sharpened into terror. She looked toward the house, then back at Sophie, searching desperately for anything she could use.

That was when an engine turned into the driveway. A silver BMW rolled to a stop behind the Mercedes.

Daniel Carter stepped out wearing a tailored navy suit, his briefcase still in one hand.

He had barely closed the door when he saw Elena pounding on the Mercedes and his daughter slumped inside.

His face changed instantly. "What is going on here?" He ran toward them. "She's locked in!"

Elena cried. "She can't breathe!" Daniel dropped his briefcase and slammed both palms against the glass.

"Sophie! Daddy's here! Hold on!" Sophie's eyelids fluttered, but she didn't sit up. Daniel grabbed the door handle and pulled so hard the car rocked slightly.

Locked. He tried another door, then another, his breathing turning ragged as panic took over.