Chess Tactic puzzle

In this blitz chess opening I missed a great tactic opportunity. Can you guess what move it was on move 12?

Solution

You will find out if you watch the end of this movie.

[Event "Rated game"]
[Site "https://lichess.org/tHm7nGxb"]
[Date "2016.10.22"]
[White "T0T0"]
[Black "bitsignal"]
[Result "0-1"]
[WhiteElo "1820"]
[BlackElo "1816"]
[PlyCount "78"]
[Variant "Standard"]
[TimeControl "180+0"]
[ECO "A45"]
[Opening "Indian Game"]
[Termination "Time forfeit"]
[Annotator "lichess.org"]

1. d4 Nf6 { A45 Indian Game } 2. e3 g6 3. Bd3 Bg7 4. c3 d6 5. Ne2 b6 6. O-O Bb7 7. f3 O-O 8. e4 e5 9. d5 c6 10. c4 cxd5 11. cxd5 Nbd7 12. b4 Ne8 13. Bb2 a5 14. a3 Rc8 15. Nd2 Qg5 16. Nb3 a4 17. Bc1 Qe7 18. Nd2 Ra8 19. Bb5 f5 20. Bxa4 Nef6 21. exf5 gxf5 22. Nc3 e4 23. fxe4 fxe4 24. Bb2 Bxd5 25. Nxd5 Nxd5 26. Bb3 Nf6 27. Rc1 Kh8 28. Nc4 e3 29. Bxf6 Rxf6 30. Rxf6 Qxf6 31. Qxd5 Qf2+ 32. Kh1 Rf8 33. Qxd6 e2 34. h3 e1=Q+ 35. Rxe1 Qxe1+ 36. Kh2 Qf2 37. Qg3 Qf6 38. Nd6 Qe7 39. h4 Be5 { White forfeits on time } 0-1