Loki

The agency that policed time is coming apart, and the only person who can hold it together is the one who broke it.

The first season ended by removing the thing that kept a single timeline in place. The second is about the machinery failing: an organisation that never understood what it was maintaining, a loom that cannot take the load, and a man slipping uncontrollably through his own history while trying to fix it.

It resolves into a choice rather than a fight, which is unusual here, and the choice is made by the character least likely to make it.