Whose Hellos Are These, Anyway?

In a world where greetings have been mysteriously stolen, you play as an eccentric detective in a bustling city where everyone has suddenly forgotten how to say 'hello.' Your task is to unravel the riddle that led to this peculiar phenomenon, journeying through quirky neighborhoods, interrogating oddball characters who might hold the key, and piecing together bizarre clues. Face off against the elusive 'Greeting Gang,' who thrive in chaos and revel in the absence of pleasantries. Can you restore the power of the greeting before silence becomes the new norm?