The three made their way back to the penthouse. Doc waited outside in the Delorean while Marty and Ally went inside to confront Biff. They stood outside of the den, both hearing 'A Fist Full of Dollars' playing on the tv and two women giggling.
Marty carefully opens the door and peeks inside, seeing who was making those noises. He shuts the door and looks back at Ally.
"Ally, I need you to stay out here," Marty said quietly. Ally lifted her head up to look at him. "Why, Marty?" Ally protested, "I gotta come in there with you," "I can't risk you getting hurt again, Ally. Please, do as I'm telling you," Marty says. He had to keep his little sister safe from Biff, especially after seeing him laying a hand on her before.
"Marty, I'm a part of this plan too. I understand you want me safe, but you forget that I can handle my own too. Please, let me help you," Ally said in the most convincing tone she could muster. Marty saw the determination in her eyes. "Fine. But stay close to me," Marty said, giving in.
They enter the den and see Biff in a hot tub with two women, neither of which were their mother. 'Ugh, this two-timing son of a bitch,' Ally thought in disgust. But they had no time to discuss why Biff is a cheating scumbag.
On the tv, Clint Eastwood revealed that he was wearing a bulletproof vest, which excited Biff. "Great friggin' flick! This guy is brilliant!" he laughed uproariously. Marty had taken the remote and switched the tv off.
"Hey, what the hell is-" Biff said, turning around to see Marty and Ally standing at the foot of the jacuzzi. "Ah! What the hell are you two doing in here?!" Biff yelled as the two ladies were screaming.
"Sorry, Biff, party's over," Ally spat coldly, eyebrows narrowed. Marty throws the remote in the jacuzzi water and says, "Sorry ladies," The siblings walk over to them. "How'd you two get past my security?" Biff scowled at them.
"We managed, asshole," Marty said, hands on her hips. "Yeah, well, you both got ten seconds before your asses are going to be carried out!" Biff shouted, close to grabbing a phone. "There's a little matter we need to talk about," Ally said, her voice ice-cold.
"Money? Well, forget it!" Biff said, shaking his head. Marty shook his head at Biff and said coldly, "No, not money. Grey's Sports Almanac," He said each word with a beat but deliberately. Biff stops and stares at the siblings very intently.
"You know which one we're talking about, Biff. The paperback silver cover with a jacket... And letters," Ally emphasized. Biff understood what they were talking about now. "You heard them, girls. Party's over," he says, still staring at the siblings.
After Biff makes a drink, he gets his bathrobe on and led the siblings to his office. "Alright, start talking, you two. What else do you know about that book?" Biff demanded. The siblings follow him into the penthouse office that was too rich for their own good.
"First, you tell us how you got it," Ally started. "How, where, and when?" Marty added, showing no signs of fear. "Alright, take a seat," Biff says. The siblings sit down in two separate chairs that are less than two inches away.
Biff walks over to a large painting of himself that was behind his desk. "November 12, 1955. That was when," Biff says, opening the painting to reveal a safe. "November 12, 1955? That was when we went back-" Marty started, but Ally slapped him on the leg, "That was the day of the famous Hill Valley lightning storm,"
Biff shrugs his shoulder and says, "You know your history, very good. I'll never forget that day. I had just picked my car up from the shop because I enrolled it in a drag race a few days earlier,"
"I thought your windshield got broken and you crashed into a manure truck," Ally said, crossing her arms over her chest. Biff freezes and looks back at her, "How do you know about that?" "Um… our father told us about it," Marty said. "Your father" Biff questioned.
"Before he died," Marty finished. Biff believed the story and nodded, "Yeah, right. Anyways, there I was minding my own business when a crazy codger with a cane shows up." Biff pulls a box out of the safe after opening it. "He says he's my distant relative, hmph, I don't see the resemblance," he says, putting the box on the desk.
"He says, how'd you like to be rich? So I say, sure," Biff says, opening the box and he pulls out the almanac, which was in a plastic bag. "So he lays this book on me. He says this'll tell me the outcome of every single sporting event 'til the end of the century," he says, Marty and Ally slowly rise up to get a better look at the book before Biff puts it back.
"All I have to do is bet on the winner, and I'll never lose. I ask, what's the catch? And he says, no catch, just keep it a secret," Biff gets up to put the book back in the safe, "After that he disappeared. I never saw him again,"
Marty carefully takes a matchbox from the tray on the desk and puts it in his pocket. "Oh, and he told me another thing. He said someday a crazy wild-eyed scientist or two kids may show up asking about that book. And if that ever happens…" Biff said, pulling out a 3.8 revolver from his desk. He aims it at Marty and Ally.
Ally's eyes widened in panic, grabbing for Marty. "Funny, I never thought it'd be you two," Biff said with a laugh. Marty spotted Biff's untouched scotch sitting on the table and thought of the perfect distraction. "Um, well, you're forgetting one thing. What the hell is that?!" Marty shouted, pointing behind Biff.
When Biff quickly looked behind him, Marty picked up the glass and throws it in Biff's face. The glass broke on the floor as the drink dripped from Biff's face. Marty then grabs Ally's hand and the both of them sprint as fast as they could.
"Oh, you're dead, you two sons of bitches!" Biff snarled, firing the gun at them. The two bolted up the stairs as Biff was shooting at them, destroying the railing to the stairs.
They reach the elevator and were about to use it, but 3-D, Match, and Skinhead walk out of it. They took off running to the stairs with the three goons following them.
They run down the stairs, switching stairs mid-flight. Marty pulled Ally over after getting himself over by her arms. They run up the stairs and make it to the roof. They run to the edge and don't see anything below them.
"Shit!" Marty swore, slapping the ledge. "What do we do?" Ally panted, looking around. "Why don't you two jump? Suicides will be nice and neat," Biff said from behind them. The two spin around and see Biff standing about ten feet from them.
Marty pushes his sister behind him, stepping in front of her. "What if we don't?" he said. Biff aimed his gun at the two siblings, cocking it back. "Lead poisoning," he said.
Ally looked around him, still in Marty's protection. "What about the cops, Biff?! If you kill us, that bullet will match that gun!" she shouted. "Girl, I own the police! Besides, they couldn't match up the bullet that killed your old man!" Biff spat with a sly grin.
Marty and Ally felt anger well up in their chests. Biff was the one that killed George and was proud of it. "You son of a bitch," Marty started, taking a step forward. Biff cocks his gun again, stopping him in his tracks.
Marty and Ally grab each other's hands and step up onto the ledge. "I suppose it's poetic justice. Three McFly's with the same gun!" Biff shouted, finger on the trigger.
Then, the siblings jump off of the roof. Biff is amazed that they went through with it. The Delorean rises up over the ledge with Marty and Ally on the hood, floating in mid-air. "What the hell?!" Biff exclaimed in shock at the flying car.
Doc opens the door and hits Biff on the chin, knocking him out cold. "Nice shot, Doc!" Ally complimented, bending down to look at Doc. The two climb inside the Delorean, Ally sitting between Marty and Doc. "You're not gonna believe this, we gotta go back to 1955!" Marty announced.
Doc's eyes grew big and he says, "I don't believe it!" "Yep, that's where we gotta go!" Ally announced Marty shuts the door and they fly off from Hell Valley.