Whose Hello is This, Anyway?

In a quirky, bustling metropolis, you are a witty private investigator specializing in unusual cases. Your latest assignment is an enigmatic string of mysterious greetings happening throughout the city — messages popping up on walls, phone calls that say nothing but 'hello,' and notes slipping under doors. As you delve deeper, you uncover a web of absurdities linking eccentric citizens, bizarre businesses, and a secret society dedicated to the art of greetings. Utilize your keen observational skills, interact with oddball characters, and solve puzzles that turn greeting cards into clues as you race against time to uncover what these greetings mean before they spiral into complete chaos!