Proceeding on, Ryu finally reaches Castle Rock Fortress (Wasn't he already supposed to have been there for the past two stages?), and battles his way through to Foster's lair. When he reaches it, Foster begins making a speech about how he would love to make a BIO-NOID out of Ryu, but instead, he will extract the secrets of his bloodline from his corpse, then use them to improve his experiments further. The doppelganger leaps down from the shadows and prepares to attack, but another person appears, holding a submachine gun, and orders Foster to stay his hand.
Ryu looks on with confusion, and finds that this newcomer is none other than... Irene. (Gee, gotta love these deus ex machina plot twists.) Irene explains that she had been trailing him for months, until she was attacked my Ryu's clone. She made use of her perceived death to stay in hiding to gather more information.
The doppelganger tells them they have both come this far only to die. He transforms into a superhuman beast, and Irene opens fire, only to see the bullets bounce off harmlessly. Ryu tells her to stay back, as he will settle this score once and for all.
