Black plays 3...Nxe4 followed by 4...Qh4
1.e4 e5 2.Bc4 Nf6 3.d4 Nxe4 4.dxe5 Qh4
White plays 5.Qf3 and if 5...Bc5 6.g3 Bxf2+ 7.Qxf2!(better than the book line 7.Nh3 when white has to defend for a long time and face a difficult middlegame)
if 7...Nxf2 (7...Qe7, 7...Qh5) 8.gxh4 Nxh1 9.Bd5 Nc6 10.Bf4! Nd4 11.Na3 Black's attack fizzles out and after Bxh1 Black is quality down.
3... Nxe5 4.dxe5 Bc5