It was a coincidence that MC recovered a solid evidence of ML's Killer in the 1st life. MC had also drank a drugged juice which was originally to be given to ML. Which is why after ML died, MC died after a few days.

When MC woke up, he had reincarnated in his college days with all his memories. He even meet ML and tries his best to warn him. MC is a naturally cute and caring person which is why ML fells for him.

Their first interaction was like MC just unconsciously took picture of ML

“Next time don’t take a picture in such an obvious position, someone will end up beating you up.” Di Qiuhe put his backpack on, stopped a cab, got on, and left.

After He Bai was sprayed a face of car exhaust, he looked at the camera in his arms, and realized too late, “Hey! What are you trying to say! I’m NOT puparazzi!

and at that time MC actually wanted to take picture of a girl playing with a pup.

Di Qiuhe: Xiuwen, my younger brother is cute.

Jiang Xiuwen:..... What makes you think that Di Xiasong, a hypocritical man is cute? Are you controlled by witchcraft?

Di Qiuhe: What is the qualification for Di Xiasong to be my younger brother? Does he have dimples on his face? Is he as cute as a puppy, as considerate as a puppy? Can he roll his eyes like a puppy?

Jiang Xiuwen: Who is a puppy? Wait a minute, why I feel this name is familiar..... you are not talking about that male fan of yours, are you? Is that White and Whiter that you tricked with using your second account?

Di Qiuhe: Yes, he is not only my fan, but also my junior at college, who can be called as younger brother. As his upperclassman, I shall protect him well.

Jiang Xiuwen: I have helped you to register at the hospital, the reservation for an expert, expert in psychiatry department. Do remember to go there on time, do not waste my money.

Di Qiuhe: You are jealous.

Jiang Xiuwen:..... I beg you, please take your medicine.

Jiang Xiuwen rocked the coffee cup gently and asked in a good mood, “See what? Don’t ham and haw. As a front-desk receptionist, you must be able to put thoughts into clear speech. Come on, don’t be afraid. Speak it loud.”

The girl darted a careful glance at him and made up her mind to cry out in a high voice, “He said... He said he had a few things to talk with Miss Jiang Xiuwen!”

Yikea!

The coffee Jiang Xiuwen had drunk spurted from his mouth.

and another case about ML's friend was when MC sent fruits to him which he received from ML.

“No, nothing. I notice that the fruits are very fresh, so I want to buy some for my family, too. It seems you have a good friend. Even in border province he still remembers to send you fruits. I’m a bit jealous.” He laughed, but deep in his heart, he had chopped Di Qiuhe into meat sauce. Di never gave him a call, but he had time to send fruits to He Bai. And he made such a mess for him to clean up? WTF. He should stop making shitty friends going forward.

MC unknowingly threw his phone in the pool which was the last thing his parents left him, ML jumped inside Lao San's home so security people came to catch ML for intruding. The ML jumped in the water to save MC's phone. But later remembered he couldn't swim and MC jumped to save him while Lao San jumped to help him save his phone. The Chef saw his master jumping into the pool where the intruder jumped and jumped to save him.

The security that arrived: “... ”

I love how author kept involving the alternative reality and tying it together with their current life, as well as give a HE for the alternative world's couple.

he mentions in the novel about the time his friend became a father and cried outside the room, he laughed and pointed out how he brought his camera but didn't photographed that moment, and he doesn't realize that up until he gets another chance at life and starts to value the people that are in his life

his professor also pointed out that the reason why he always got a failing mark was because his photographs didn't have any soul. He is that detached

some of you might point that MC got manipulated but no he didn't he just let it slide because he doesn't really see as a problem for him. Even though MC is detached he has a pretty strong mentality. Its in the novel that he doesnt get manipulated when ML starts acting how pitiful he is now he doesnt have a home and stuff, then MC slaps him while pretending to say oh theres a bug sorry not sorry. If he really gets manipulated I would be uncomfortable and won't be reading this story and won't even write a review about it.

you can also see at the end how the both care and treat each other as an equal.

MC had an accident and crossed over to the first world, he managed to save Quie, but he (He Bai) wants to go back to his Childish Di. The Quie in this world fell in love with Bai and was then left behind.