The Big Moment (Bolshaya sekunda) - Season 1, Episode 10: I'll probably leave.

Estranged ex-lovers, Kostya and Kira are unexpectedly thrown together again when they're asked to collaborate as script-writers on a love-story set in a music school. The script focuses on teachers Rostislav (Dmitry Lysenkov) and Arina (Evgeniya Borzykh), who are caught-up in a difficult situation, made more complicated by Arina passing off a new colleague as her boyfriend to placate her demanding mother. The real and phoney relationships, both on and off-paper (or in reality or in the script), test all the characters, and examine themes of love, trust, sex, infidelity, friendship, responsibility as well as compatibility.