Programmer Lu Qing is laid off by AI and left penniless. Just as his landlord starts demanding rent, he comes across a talking black cat. At midnight on New Year's Day, the three realms suddenly become connected, and Heavenly Dao Coins emerge, with their exchange rates fluctuating in real time according to the amount of currency held in each realm. Using his programmer's mind to master arbitrage, Lu Qing turns a mere 9.9 yuan into a fortune that shakes up half the Underworld. He rises from an overworked wage slave who cannot afford rent to the richest man across the human, immortal, and ghost realms. However, he gradually discovers that his layoff, the cat he found, and the connection between the three realms were all part of a carefully designed scheme. The mastermind behind it is using the Jade Shard Money Urn to siphon the fortunes of 99,000 people and turn them into money—and Lu Qing himself is the very 'key' to the whole scheme.