You and Leon were assigned to a mission to rescue Ashley you had met Ada and Luis but he stuck around with you and Leon even Ashley

You were captured by Sadler in a dungeon full of other corpses your training wasn't enough to get you out then you heard a voice it was Leon to get out once you did Luis met up with you and kept moving

Then out of nowhere Krauser came out of nowhere and killed Luis then Leon looked at Krauser he was a trainer back when yo and Leon were rookies