David Tennant’s best-known TV roles are good guys; his Criminal character could have been wrongly accused or a monstrous perpetrator.
I didn’t know where the episode was going until the very end, and that was fantastic.
If you’re on the fence about Criminal, I would recommend at least trying the first episode with Tennant in the spotlight.
When his Criminal character starts to spin his version of events, you want to believe him, and it’s an intense hour of back-and-forth before you find out whether or not he should have been trusted.