The story of Hello Mr Billion centres on the overnight journey to riches story of Mr Duoyu Wang. Mr Wang is a goalkeeper for a minor league soccer team—Diaxang. Mr Wang is terrible at his job. The thirty-seven-year-old demonstrates his imagined prowess as a goalkeeper to Mr Jin, who is hiring. The show is an eyesore.
Mr Wang’s career has been downhill in recent years. He was sent out of the field for biting an opponent’s leg. He pretended to be a woman and played alongside a female team. He worked as a human sushi plate for women and even modelled for a nude painting. Mr Jin reveals that he is not hiring Wang to play on his team but to purposely fail in his duty to catch shots against Diaxang. Wang rejects this offer and promises Mr Jin that his team will not win any shot against Diaxang. However, on match day, Wang catches one shot and loses the other five goals as he gets lost in his celebration of saving one goal. Mr Jin watches with the crowd and laughs at the spectacle.
Wang is praised by players of the opposing team and kicked out of his team. Qiang Zhuang, Wang’s best friend and teammate, visits Wang when he doesn’t leave the house for days. He convinces him to talk to their coach to get his position back. The coach is not willing to let Wang back into the team. He has even been replaced by a dog. Qiang threatens to leave the team if Wang is not accepted back, but he gets a different reaction from the coach.
Like Wang, Qiang is kicked out of the team. They stop by a red light on their way back home. A traffic racketeer makes a show of getting hit by them and throws his vegetables into the air, and lays on the ground. Wang and Qiang know what this is and confront him. They lift him and bump him into the vehicle. They even use his body to wipe the windscreen that got bird poop on it. A young woman sees them and accuses them of harassing the racketeerer.
They end up behind bars but get released all of a sudden. Mr Jin has paid their bail. He tells Wang that he doesn’t own a team and that their earlier meeting had been a test. He takes them to his office and introduces Wang to Mr Yin and Mr Lai of Guang Ming Trust Fund while Qiang waits outside. They tell Wang about his unknown grand-uncle who was considered dead by the family.
They tell him that his great-uncle has 30-billion inheritance left behind for Wang. However, there is a condition that Wang must meet. Through a video recording, his great-uncle explains to Wang that he must spend one billion yuan within a month under some conditions. Wang is not allowed to donate the money to charity, he is not allowed to spend it on any other person’s behalf, and he is not to tell anyone he is trying to finish spending one billion won in one month. He can’t invest the money in business. He cannot buy gifts for anyone. He is only allowed to spend the money on himself, and he can hire up to a hundred staff.
He cannot buy gifts and burn them. He cannot hike up market prices to exhaust the money. Along with these, there’s a coward clause Wang can settle for. He will be given ten billion won if he forfeits the challenge, or he can make a bet where he either wins the challenge or loses the 30 billion won.
If Wang loses the challenge, the money will be given to Mr Yin and Mr Lai’s trust fund as a charity donation. Wang accepts the challenge and goes to see the cash with Qiang. They lose balance when they see the money. Mr Jin appoints an accountant from his staff to keep track of the money spent by Wang. the account is Xia Zhu, the young lady who got him and Qiang arrested earlier. Mr Wang hires her in order to get revenge on her. They are leaving the bank with bags of money when the security guard stops them.
The chief guard puts the security guard right, but Wang offers to pay the guards the worth of presidential guards if they work with him, and they agree. Wang and Qiang return to their team field. Wang shares his plan to rent the whole team and Hengtai—another reputable team, with the coach, and the team thinks he’s crazy. The coach offers them money to visit the hospital for a mental health checkup.
To prove his point, Wang calls in an evacuator to drop a huge pile of money in front of the team. A fleet of cars comes to carry Wang and the team. Xia Zhu is travelling in a car with Wang and makes him understand that she has a boyfriend when he tries to hit on her. The crew arrive at a five-star hotel that only admits customers with membership cards. Wang makes a ridiculously high offer to the manager, who agrees to the deal to host only the team in the hotel for one month. Since Wang rented the team, he is allowed to buy things for them.
During a banquet, Wang tries to persuade Xia Zhu again, but she rejects him. Wang announces that he would be opening a new investment company, and it would be controlled by Qiang, who he believes is not intelligent enough to make any profits—so he could lose money. Wang gets an expensive haircut and starts renting everything—clothes, shoes—at ridiculously high prices. Xia Zhu tries to talk to Wang that he will lose his money in six months if he continues spending like that.
Wang meets her boyfriend when he comes to take her to one of his talks. Wang offers his two piles of money after he turns down his offering of a drink. Jiannan Liu takes the drink and ignores his girlfriend, who is shocked. Out of nowhere, Jiannan offers to work as a gardener for Wang. Wang accepts and promises to pay the highest salary in the state. Xia Zhu is disappointed and forbids him from seeing her.
A weird man shows up seeking investment for an outrageous project that lets you swim on land. Wang sees that the idea will not work, and he agrees to fund it. Wang asks everyone with a dream to tell him what they need. He approves so many projects, convinced that they will fail. After a nightlong massage, Wang dismisses Sasha, but she refuses to go and tries to seduce Wang. wang tries to run away, but she corners him to a statue and starts wiping him with her long ponytail. Xia Zhu arrives just in time to save him.
He appreciates her later for this and receives a really warm greeting from his staff, including Jiannan, who has resumed work as a gardener. Xia breaks up with Jiannan, but he is unfazed. Wang rents an expensive golf field for Diaxang to train on. He meets Mr Yin and Mr Lai on the golf. Wang also sees Sasha with them and figures that she was hired by them.
Wang invites them to lunch and purposely insults them. He is intrigued when one of them quotes Mr Lafitte, a very famous businessman. Wang does the impossible by inviting Mr Lafitte to China for lunch. He asks him for failed business ideas, and this upsets Mr Lafitte. He leaves angrily, and this upsets Xia Zhu, who doesn’t work with another company that will go bankrupt.
She is mad that she has been called a black widow, but Wang assures her that she is the mascot of his company. Wang is still spending lavishly when he receives news that the bad investments he made were actually paying off and making him more money. This makes him mad. Mr Yin and Mr Lai are having a swell time watching Wang fail the challenge. Wang is woken up from a nightmare about his great-uncle by Qiang. He makes him meet a man with one bad eye. Wang immediately agrees to give the money without waiting to hear his story. Qiang promises to set up fireworks when the idea yields results.
Xia Zhu is sulking alone in her apartment on her birthday when Jiannan comes knocking. She drops his flowers on a table and smashes the cake in his face when he asks her to convince Wang for funds to sponsor a book idea he has. She kicks him out and goes to see Wang. She is surprised by an elaborate show of fireworks. Xia is grateful for the birthday present, and Wang sings a birthday song for her, pretending to be already aware of the date. Xia is touched by the present but insists that she and Wang can be nothing more than the relationship between an uncle, elder brother and younger sister. Wang puts up her pictures on billboards throughout the city to convince her to give him a chance. Xia gets unwanted public attention because of this. She calls Wang t to fix it, but he invites her to a concert instead. She gets into a taxi to go back home. The taxi stops at a traffic light, and the racketeer returns and makes the same show.
Xia Zhu can now see that Wang was not at fault. She goes to see Wang and tells him she wants to get to know him better. She attends the concert in the hotel and has fun with the musician—who is her favourite singer and Wang. They go out for dinner and play soccer with some kids at the park. They have a lovely walk under the evening sky, giggling and holding on to one another.
Meanwhile, Mr Yin and Mr Lai have invited Jiannan over. They reveal the secret of Wang’s riches to him and offer him money to sabotage Wang’s plans. Wang meets his team partying instead of training and learns that they are celebrating because the company has earned ten billion. Wang is distressed. He goes missing and announces a scheme to go bankrupt to the entire public. He establishes the fat insurance program with the approval of Mr Jin. He challenges the public to lose one kg of calories for thousands of yuan. The participants only need one yuan to sign up. Mr Yin and Mr Lai are upset about the plan, but Mr Jin explains to them that he has set up a legal business and not a charity organization.
The game day arrives, and eighty percent of the stadium is on Hengtai’s side. Diaxiang’s team arrives in helicopters, but the coach ruins that wonderful moment when he vomits from taking too much alcohol. The match starts, and everyone’s cheering for Hentai, including Jiannan. The game turns to Hengtai’s side as Wang fails to save many shots. The star player on the opposite side is given a red flag after Qiang intentionally upsets him. After the first half, Wang scolds the team for leaving everything to him. They decide to activate plan B. Xia Zhu spots Jiannan and goes to confront him. He explains to her that Wang doesn’t really love her but is using her to spend his money so that he can acquire a more significant amount. He tells her of his plan to sabotage Wang’s plans. Xia Zhu kicks him and runs to report to Mr Jin. Jiannan chases after her.
The match ends with the stadium cheering for Diaxiang after their courageous defence against Hengtai–stopping the opposite team from winning two digits score. Wang’s team is presented with the real trophy, and his celebration is cut short when he receives a call that Xia has been kidnapped. He confronts Mr Yin and Mr Lai. They confess that they told Jiannan about everything but swear that they didn’t get Xia kidnapped. The kidnapper is Mr Jin, and he prepared a fake video of Jinnian getting killed. Wang calls Mr Jin and asks for his permission to use the money to free up Xia, but Mr Jin says it cannot be allowed. The plan is the third and final test Wang is to face before he can inherit his great-uncle’s wealth. Xia is convinced that Wang will not come to save her, but Mr Jin has faith in him. Wang is devastated and decides to get drunk to forget his predicament.
Time runs out, and Mr Jin is disappointed. As the goons leave the building, they meet Wang on the staircase covered by guards. He closes his eyes shut and tells the kidnapper to take his money and let Xia go. Mr Jin tells him that he has passed the final test, and Wang is relieved. He marries Xia and gets her pregnant. They approach a charity foundation and are about to donate all the wealth away when the baby in Xia’s stomach kicks. They then think of their baby and ask the attendant if it’s okay to take out some amount for their baby. She agrees to it and they take a lot of time listing the numerous things their baby will need.