The mysterious Phantom Thief A can slip through any security and steal whatever she targets.

In reality, she is a bright and bubbly high school senior.

One day, Vox, the young CEO of a massive corporation, transfers into her class.

However, he had previously come face-to-face with Phantom Thief A when she broke into VoxTek. Realizing the thief he thought was a man is actually the schoolgirl standing before him—

"...Yo. Long time no see, since yesterday."

With those words, a chill runs down her spine.

—Her identity is blown.

Since then, Vox has been constantly pestering her, dropping cryptic hints.

It's as if he's enjoying the fact that he knows her secret.

The fleeing Phantom Thief A and the Vox who corners her.

Their strange game of cat and mouse begins.