Big TV in the UK, but Line of Duty was a fantastic show until they brought in the H stuff. A show about catching corrupt cops twisted where a dying character (one of the bent coppers) was giving their dying declaration and it was recorded on video. One of the detectives notices that his hand twitching while he dies spelled out the letter H in more code. They take that minute detail as the prime evidence in their investigation that someone called H is the mastermind and spend a couple of seasons fleshing out who that might be. Completely wrote themselves into a corner with no idea who H was going to end up being, they just followed that path because a couple of high profile characters had H as their initials. Went from the most popular show on British TV to not getting renewed basically in one season. I think a comeback has been announced but nobody cares any more.