Well, hello. In the Episode 5 of Heated Rivalry during the Rozanov father funeral (with brownies on vodka) plays the beautiful song. It begins with Ilya staring through the window and ends before the dialogue between brothers. I saw people on the Internet recognised it as church choir song and asking about the name. But they get incorrect answers. Also it seems the song didn't end up in the official playlist. So here it is. It's "My sinful soul" (Душа моя прегрешная) Russian Orthodox Chant. But not simply Orthodox, it's starovery (staroobryadtsy or Old Believers) chant. Not quite canonical and very rare. The song lyrics was published at the beginning of 20th century. And the vocal and instrumental arrangement of the song was prepared by Andrey Kotov, director of the Sirin ensemble. The lyrics heard in the Episode are:
Ты плачь, душа, рыдай всегда — Тем утешишься! Не поспеешь ты тогда плакати, Когда приидет смерть.
Which means:
You weep, my soul, cry eternally — thus you'll be consoled! You won't be in time to weep, when comes the death.
Fulltext in Russian here.
I've linked the closest version of song to the one from the series:
Please correct me if I'm wrong anywhere. Thank you!
