Scotch gambit - Dubois-Reti defence
1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Bc4 Nf6
White plays the king's pawn to e4. Black moves the king's pawn to e5. White develops the knight to f3.
Black develops the knight to c6. White plays the queen's pawn to d4. Black captures on d4 with the king's pawn.
White develops the light-squared bishop to c4. Black moves the knight to f6.