To refresh your mind: Delilah was never murdered. Chloe and Lucifer met at the Gillian Taylor case, what was in the canon season two, episode one.
In chapter five someone shot Chloe, Lucifer protected her with his wings: that is how Chloe, Ella and Trixie found out Lucifer is the devil. All three ladies took that reveal well.
Lucifer also realized Chloe is something special: immune to his powers and his dad listens to her prayer. Chloe prefers to think that last fact was just coincidence.
Dan found out in chapter nine and Chloe asked Lucifer how he could ignore his dad's orders if he didn't have free will.
They are dating, first date was a visit to North Norway to see the northern lights. They do sleep together. Previous chapter they realized God listened to more prayers of Chloe. Lucifer wanted to know why dad listens to her… so dad showed up in the last lines of chapter ten.
Chapter eleven:Feeling responsible
"Why are you here?" Lucifer almost shouted.
"Well, Chloe asked for answers," the visitor answered. "Are you going to introduce us?"
"You know how she is."
The man sighed, then smiled.
"You are…" Chloe hesitated. "Lucifer's dad?"
"I am." He put his hands on her shoulders. "It's good to finally meet you, Chloe." She got a kiss on both cheeks and then God turned to Ella to kiss and greet her. "My dear Ella. The brightest soul on Earth."
"Me?" Ella stammered.
"You, my girl." God turned to Lucifer. "Good. Ask."
"Why do you listen to the detective's prayers? Why did you put her on my path? What do you want from me? From her?"
"From the two of you," God answered with a node of his head. "And I will give a hint on what I need from the two of you. But first a question, boy. If Chloe would be in danger, what would you do to save her?"
Lucifer stared for some seconds at his dad, before he snapped. "Everything. Without limits. I will start Armageddon here and now if you hurt her."
"And to save Beatrice?"
"Also everything," Lucifer said.
"And Ella?"
Lucifer looked a bit confused at Ella. "Of course I would do everything to save her. What point do you want to make?"
God gave him a quick smile and turned to Chloe. "Why did you become a cop?"
"To help people."
"As much people as possible?"
"Yes," Chloe said. "Well. I'm only human. I can't do miracles."
"Can you come to the point?" Lucifer said to his dad. "And then leave?"
"The point? I already told you: I gave the cosmological constant a wrong value."
"Then change it and leave us alone," Lucifer almost shouted.
God shook his head. "Let me explain…"
"What is that constant?" Chloe asked.
"Einstein called it his biggest mistake," God said. "He put in the formulas of the theory of relativity. Later he thought the constant didn't exist and called it his mistake. But as astronomers in 1998 discovered it does exist. It has always existed. And at the moment of the Big Bang I gave it a wrong value. A value that would have made the universe collapse in a few million years. So, no stars, no planets, no humans."
"But the universe still exists," Ella whispered.
"Indeed, Ella. My future self managed to send a warning to my past self, so microseconds after the Big Bang I could change it to a better value."
"So?" Lucifer interrupted. "Changed. Problem solved. No need to disturb us. Please leave."
"My future self, that is the me of now, still has to send that warning. I have to send it or the universe will collapse. All humans will be wiped from existence. Chloe, Beatrice, Ella, they will burn in a fire hotter than the center of the sun."
"Then what you waiting for? Send yourself that message."
"How?" God said and looked head tilted at Lucifer. "I can't go myself. I'm too much interwoven with this universe. My traveling through time would tear up space and time. I need help. You said you would do anything to save Chloe."
"I…" Lucifer opened his mouth and closed it again, swallowed. "I have no idea how to help."
God turned to Chloe. "You wanted to help people. I need help to save all eight billion humans alive and all the billions that will be born in the future."
"Tell me what to do," Chloe whispered.
God smiled. "You alone can't help, my daughter. Lucifer alone can't either. But you two together will, be change, without realizing, one day give my a way to warn my past self."
"How?" Chloe asked.
God shook his head. "You should not know. When it happens, you will not relate it to my problem. Well, I promise I will explain later, fifteen years or so after you provide me what I need."
"I was hoping for an answer, but you want to keep it vague and mysterious," Lucifer snapped.
"Fifteen years later I will explain, but knowing the future will influence your doings. So: Chloe is not here to endanger you. I only brought you together to save the universe."
"Will it harm the detective?"
"She will be healthy and happy," God said.
"Why can't you say yes or no?"
"I will explain in fifteen years. To both at you and you will listen hand in hand."
"Hand in hand? You made us fall in love?" Chloe asked.
"No, my daughter. That was your own decision. I only made sure you were not influenced by his powers, so you could get to know the real Lucifer underneath that facade of a player and nightclub owner."
Chloe gave it a thought and then asked: "You're not going to tell more about how we will help?"
"You know the maximum you should know."
Chloe looked at Lucifer, back at his dad and asked: "Free will?"
"My son wanted to have it. I can't give it to an already existing angel. He had to develop it himself."
"So you did put him in hell for eternity…"
"Less than thirty thousand Earth years," God interrupted her.
Chloe ignored that. "… for eternity without explaining. That is just terrible. I mean, you kid plays up and you abandon him."
"His literal words were: I don't care. Whatever you need to do, give me free will. Do anything that is needed. Those words were shouted."
Chloe looked at Lucifer again.
"Ah. Yes. Well." He cleared his throat. "I might have said that."
"You might have said that?" God asked.
"Well. I did say it. But why didn't you explain?"
"Then you wouldn't have been angry and you wouldn't have developed free will."
"So it was all planned?" Lucifer asked.
"Mm. I overlooked one thing. Some of my children were shocked enough to ask me to forgive you. I told them not to talk about it, but it appeared they also got some free will: your sisters Raziel, Saraquel, Remiel and Zuriel and your brothers Zadkiel and Amenadiel. They kept asking me to forgive you."
"Amenadiel?" Lucifer asked. "He tells me to go back to hell each month."
"Because I order him to do, but after each visit he comes to me and tells me you really don't do any harm on Earth. A side effect I hadn't foreseen. I really can't say more. The two of you will one day do the thing that will help me. I better go before saying too much."
"But…" Chloe started.
"No time for it," God said with a wink at Ella. Ella frowned and looked head tilted at him.
"But…" Lucifer said.
"No time for that either." Again with a wink at Ella.
"Off you go without hat or pockethandkerchief or money." Ella laughed. "How does that work? Do you have to read books?"
"No. I just know what's in any book. And I also just know you would recognize it." He turned to pat Lucifer on the shoulder, who with a grim look stepped back. Then God kissed Chloe and Ella and said to Ella: "I have a small task for you: remind Chloe at the right moment that she won't know when the two of them gives that help. We will meet again, girl." And the next moment God was gone.
"All manipulations," Lucifer mumbled after a few seconds of silence, but he sounded less angry than normal when he used the word manipulations.
"You don't believe your dad?" Chloe asked.
"O, I do. He spoke the truth. He just didn't tell everything. Why not?"
"We shouldn't know too much?" Chloe answered.
"Why didn't dad say you wouldn't be hurt? If you get hurt…"
Chloe interrupted him. "He promised I would be healthy and happy. And getting hurt is part of my job, Lucifer. I am a cop."
"I will not allow that you get hurt."
"We will see what will happen, how we will help," Chloe said. She embraced him and kissed him to stop the argument.
With a grin Ella raised. "I go to my room."
Next day brought a new case. Ella did her forensics while Chloe and Lucifer interviewed neighbors.
"What can you tell us?" Chloe asked when they came back to the crime scene.
"The victim was sitting in this chair, reading that book." Ella pointed.
Chloe bent slightly to have a better look at the book. "Sci-fi. Does it deal with time travel?"
Ella gave her a questioning look. "No. Why?"
"Lucifer and I have to help Lucifer's dad."
"Chloe," Ella said. "No author has any idea how that could be done."
Chloe nodded. "You might be right, but I'm given this responsibility… I must be sure…"
"Ah." Ella shook her head. "You will not know when you give that help, remember. Anyway. I know the book, I've read it a few years ago. No time travel in that book."
"Let's just do the case, detective," Lucifer said with a smile.
They just did the case and arrested the killer.
Chloe had promised Maze an all-girls-night, so she had asked Ella and Linda to join them and the four women had chosen to go to another place than the Lux.
"And just to be sure: drinking is part of this?" Maze asked.
"Of course. We drink," Ella said and waved at the bartender of that bar.
"Don't try to keep up with Maze," Linda warned her. "She's a demon. Five bottles of vodka each hour won't effect her. And we do women bonding, Maze."
"Talk about how good the boys are in bed?"
"And feelings, Maze," Linda said.
"I have no feelings. I booze, I bone, I fight."
"Fine," Linda said. "I'll start. Um... I worked my way through med school as a phone sex operator. 1-800- ProfessorFeelGood."
Maze laughed. "I would totally call that. Can we still do a session?"
"Nice," Ella said. "Okay. I'll go next, I guess. Um… I used to steal cars."
"Really? Chloe? What do you want to add?"
"Me?" Chloe looked a bit confused at her friends. "You know me. I'm just me…"
"If you have nothing else, tell us how Dan is in bed," Maze interrupted her.
"O, yeah. Gossip," Ella said.
Chloe tried to get away from the subject. But Maze seemed to know exactly what she wanted to hear and asked details until Linda said: "That's enough Maze. Shall we talk about something else?"
"How is Lucifer in bed?" Maze proposed.
Linda gave Chloe a quick look and shook her head. "Not about present boyfriends."
Ella nodded. "Better not. Previous ones. My first time was with a man twice my age, I was twelve."
"That's not legal," Chloe interrupted her.
"It was my decision," Ella said and shrugged. "He was sweet and I learned a lot from it."
"My first time was with Nick, a boy next door," Linda said. "We were both fourteen and it was a disaster." She looked aside and stopped talking. "What the…"
"What?" Maze asked.
"That's him." Linda pointed at a group of four men and three women at the other end of the bar. "The portly guy with the green sweater. That is Nick. What a coincidence."
"You didn't see him since you were fourteen?" Ella asked.
"What? No, no. A few years ago I saw him at a reception, when two teachers of our elementary school retired. He is a teacher himself now. Teaching physics at a high school."
"Wait a second," Chloe said, triggered earlier by the word coincidence. "Physics? What does he know about Einstein and the cosmological constant?"
"Is that what God told you about?" Linda asked.
"Decker," Ella said. "God told us you will give the help together with Lucifer without knowing. Lucifer is not here."
Chloe shook her head. "I'm feeling responsible, Ella. He might have a clue." She walked to the group of seven and tapped the man with the green sweater on the shoulder. "Nick?"
The man turned around and gave her a questioning look. "Yeah?"
"Did you study physics?"
"I did st…" Nick was interrupted by one of the women.
"Hey, you. Stay away. He is taken." The woman tried to push Chloe away. Chloe reacted by blocking the stretched arm of the woman, grab the other arm and turn it on the woman's back.
"I only ask some questions," Chloe started to say. Too late she realized she had stepped into the middle of the group and both her hands were holding the woman.
"Leave her," one of the men shouted, while one of the others hit her full with his fist on her face.
Chloe had to let the woman go to defend herself against the two men and one of the women who also tried to hit her. The moment she tried to step back out of the group Maze was next to her. The demoness lifted one of the men and threw him yards away as if he weighted no more than a few pounds. Next moment Maze kicked the woman threatening Chloe and sent her to the floor. On her other side Ella jumped on one of the other women.
"Maze, Ella," Linda shouted. "Remember... aggression is not the answer, okay. Clearly, that woman is having some serious trust issues."
Maze and Ella didn't pay attention. Ella had worked the woman to the floor, Maze had knocked two more men down.
"Clearly…" Linda said behind them.
Maze had now grabbed Nick and single handed lifted him from the floor.
"Maze, I wasn't done questioning him," Chloe shouted.
The demoness laughed, dropped the man in a chair and said. "Carry on."
"Hey," Chloe said. "Did you study physics?"
"Engineering, Architecture," Nick said with a bewildered look in his eyes.
"What do you know of the cosmological constant?"
"What?"
Maze grabbed his shirt and lifted him a few inches. "Just answer her question."
"I don't know. Something of the theory of relativity. Please, I really don't know."
For a second Maze stared in his eyes and then whispered to Chloe. "He really doesn't know."
Chloe shrugged. "Ok. Let him go."
Maze dropped Nick in the chair and the three women walked back to Linda. "I now see what the Big Guy meant," Ella said with a smile. "I had to remind you you will not know when you help him."
Before Chloe could react the owner of the bar came with two of the bar's bouncers with him. "You started a fight," he said. "You damaged a table and some chairs."
"So?" Maze asked. With her right hand she took a golden credit card out of a pocket. "Just take the payment, also for the drinks. We're leaving anyway. The Lux has much better booze."
One of the bouncers stepped forward and bent over to her, probably trying to be impressive. Maze just lifted him with her left hand and threw him on a table yards away.
"Include that wreckage," Maze said, waving with the credit card in the direction of the remainders of the table.
They continued the girl talk and gossip in a booth in the Lux. An hour after midnight Lucifer joined them and looked frowning at Chloe. "Your cheek is brushed, detective. What happened?"
The four told him of the bar fight. "… and I told her she won't know when you two will help your dad."
Chloe shrugged. "I'm just all the time thinking about it. I feel responsible. I'm responsible."
Later in the penthouse Lucifer enfolded his wings and used a feather to heal the brush on Chloe's cheek. Then he wrapped the wings around her and used his hands to touch the front of her body and the wings to caress her back at the same time.
"Unfair tricks, Lucifer Morningstar," she whispered in his ear.
"Only to help you ignore my dad's story. You should forget that silly cosmological constant."
"Ok, ok. I give in." She moaned. "It's working. Carry me to your bed. I will forget that responsibility. "She giggled. "Us making love will not be the action that solves your dad's problem."