A best in show has emerged from television’s busiest summer ever. The distinction may strike some as improbable during the season in which popcorn entertainment generally rules. This fine program has nothing to do with aliens, zombies, cops or killers. It is a first-class remake of a historical drama from the Seventies that probably sounds like a snooze. And while such declarations are generally a matter of individual taste, from where I sit it’s more entertaining than anything else on broadcast, cable or stream right now.