The official website provides a detailed synopsis for the first episode:
The panels frequently use over-the-shoulder shots—showing one partner watching the other through a crack in the door. This "gaze" is a metaphor for the new, poisoned lens through which they will now see each other forever. Every smile, every delayed text, every night out with "friends" will now be filtered through the memory of the swap.
The mutual friend. He is the one who propositions the "exchange" and engages in an affair with Kanade. He is portrayed as more aggressive and less conflicted about his actions.
The series illustrates how easily decades of built-in trust can be eradicated by a single choice. The characters discover that knowing a spouse's history does not mean knowing the depths of their hidden impulses. 2. The Illusion of Consent
