First of all, it's got the awesome Katheryn Winnick, a very believable female action star in her own right (she needs no stunt doubles); she should have been on the main cast from the start. But even more compelling is the "secondary" storyline with Finch and Root, and a Trojan horse that Finch had installed on the computer of an unwitting Samaritan accomplice earlier in season 4; their relationship has never been more complicated, and we witness a "series first": the death threat to a number coming from someone inside the group (a variation on an earlier theme of the Machine asking all of them to kill a man). Do not skip "Skip". *** out of 4.