Everyone is obsessed with Unison, the social network that knows you better than you know yourself. Everyone who can afford it, that is. Living beneath the vast ceiling that separates Eastern Seaboard City into rich topside and poor sub-canopy zones, fifteen-year-old Mistletoe can only dream of logging in and has to make do with technological hand-me-downs. Worlds collide when Ambrose Truax, the privileged heir to the Unison empire, wanders into the dangerous sub-canopy streets and Mistletoe saves him from suspicious, uniformed men. They soon discover that they share eerily similar dreams, hinting at a significant past. Together, Ambrose and Mistletoe begin to unravel the mystery of their identities and learn that they're pawns in a bigger game: the Unison 3.0 upgrade, a whole new kind of Friendship.

The primary target is the A&P mechanic who wants to learn what information he/she needs to know/seek according to service on a Cessna 172, the secondary target is owners who want to do service according to Preventive maintenance FAR 43, Appendix A or Limited Pilot Owner Maintenance EASA No 2042/2003, PART-M, Appendix VIII.

List of members in v. 7-15, 17, 19-20.