Death Note

A genius high school student finds a notebook that kills anyone whose name is written in it. He decides to become God. An equally genius detective hunts him. This 37-episode cat-and-mouse thriller is the perfect gateway anime because it doesn't feel like anime — no fan service, no filler arcs, no 200-episode commitment. The psychological warfare between Light Yagami and L is riveting television by any standard. The manga sold 30 million copies and the anime is on Netflix in 190 countries. You can finish it in a weekend.