You're reaching out for meaning, but the wrong thing is reaching back."
What initially appeared to be a "case of the week" installment (albeit a very fun, intriguing one that aimed to get Finch back on his feet) took a very cool and powerful turn in the middle when our heroes discovered that Samaritan itself was behind the super-genius city-wide scavenger hunt that young, lost Claire - a number - was participating in.
I usually don't expect all that much from episodes this early in the season so "Nautilus" was a welcome surprise from a mythology standpoint. And all the parts really flowed together well and turned this chapter into both a Finch redemption episode and a sort of "Claire turns to the dark side" episode. All capped off with some great Portishead music there at the end when Claire flipped the final switch and saw her hopes for a more meaningful existence, momentarily, go up in smoke.