A strange app: [Vertical Reading]

"In order to protect your life, please repay as soon as possible," the app stated. Kaito suddenly needed 12 million yen because his mother was seriously injured in an accident. He stumbled upon a suspicious app that offered him that amount, and overjoyed, he downloaded it, but it wasn't free... He was given terrifying missions one after another, and the app wouldn't disappear no matter what. This curse...