This is the first time I participate in this contest and I'm emotional XD
Btw this is a little crossover that i hope like you (please you comment in english, i don't know the russian ;)
The story is that both for homura that Okabe, dead a dear friend (Madoka&Mayruri) and they travel back in time to change the fate without success. For change this fate homura creates a "manga" to find the right person with whom to change the past and she finds Okabe, which built a time machine that for to work correctly it needs a higher power (the key of homura).
Homura deliver the key to Okabe and he (in the end to video) will definitely change the past.

I hope that this plot you understand at least a little in the video XD

This is my making of: http://i47.tinypic.com/23s8c5u.jpg