Chapter 1: Nightcall
Following the events of Hitman, Agent 47 embarks on a mission to hunt the mysterious "Shadow Client" and disassemble his militia. His first lead is the location of one of the Shadow Client's lieutenants, Alma Reynard. 47 is able to gain some intel on the Shadow Client's activities from Reynard's home in New Zealand before eliminating her. Impressed with 47's performance, Providence authorizes him and the ICA to hunt down the rest of the Shadow Client's militia. When 47 asks Diana why the ICA would be willing to work with Providence, she replies that both organizations share interests in putting a stop to the Shadow Client, whose activities are now causing a global panic. She also reveals that Providence secretly promised to her to reveal 47's past.
Chapter 2: The Finish Line
Following the intel gained from Reynard, 47 is sent to Miami to assassinate tech giant Robert Knox and his daughter Sierra, the owner and heir of Kronstadt Industries. Not only have they secretly sold advanced weapons to war criminals, but they are also Providence members who defected to the Shadow Client's side, presumably to protect themselves from his attacks. Meanwhile, the remaining members of Providence descend into consternation as more of their operatives are killed worldwide. Despite this, Providence manages to identify the Shadow Client as Lucas Grey, the former head of security to deceased Providence key-holder Eugene Cobb. Grey, now located in Central Europe, pursues his own plans with hacktivist Olivia Hall and insists that they need 47's help if they are to dismantle Providence.
Chapter 3: Three-Headed Serpent
47 heads to Colombia next in order to assassinate drug lord Rico Delgado and his top lieutenants, who have been using their smuggling network to aid Grey and his militia. Diana reports the mission's success to Providence while visiting the graves of her family in Surrey. Flashbacks reveal that she witnessed her parents being killed by a car bomb after they attempted to bring the company responsible for her brother's death to court. Shortly after Grey steals an item from the Ether Corporation in Johannesburg, his militia use a hostage situation to publicly reveal Providence's existence.
Chapter 4: Chasing a Ghost
47 is then sent to Mumbai to track down and eliminate the pirates who killed a Providence operative in Shanghai. After the mission, 47 follows Grey's trail to Romania, back to the very same asylum where he was created by Dr. Ort-Meyer. He encounters Grey, who reveals that they were both previously kept in the lab to be raised as assassins for Providence. 47 regains some of his memories, remembering that Grey was Subject 6, and that they both made a pact to take revenge on those responsible for turning them into assassins.
The revelation leads to Diana meeting with Grey and Hall in Berlin. Grey reveals that Ort-Meyer, the scientist responsible for his and Agent 47's creation, was a member of Providence, who are controlled by a leader known as "the Constant" and three executive members known as "the Partners." After Grey and 47's original plan to take down the Partners failed, they decided to erase 47's memories, though Grey was able to escape before his memories were wiped. Grey's current objective is to capture the Constant, as he is the only person who knows the identities of the Partners. His only lead, however, is that 47 knew the identity of the first Constant. Grey then reveals that the item he had stolen from the Ether Corporation was an antidote that may counteract 47's memory loss. Initially reluctant to work with Grey, Diana eventually abides by 47's wish to take the antidote.
Chapter 5: Another Life
The antidote allows 47 to remember that the first Constant was a legendary Cold War spymaster codenamed "Janus". In order to get close to Janus, Diana files a false report implicating Janus as the true Shadow Client while claiming Grey was just a subordinate, giving 47 pretext to infiltrate Janus' home in the suburbs of Vermont.
Chapter 6: The Ark Society
Investigating several clues, Agent 47 finds evidence that Janus was planning to meet the Constant at a gala held by "The Ark Society," a plutocratic survivalist group created within Providence. Hall is able to pinpoint the meeting location on a remote island in the North Atlantic, but they find out that the Constant, revealed as the man who hired Diana and 47 at the end of Hitman, has implanted himself with a suicide chip that will instantly release lethal poison into his body if he is compromised. 47 is then dispatched to eliminate Zoe and Sophia Washington, twin sisters and newly appointed chairwomen of the Ark Society who each hold a kill-switch for the Constant. Once the Washington sisters are neutralized, 47 and Grey proceed to capture and extract the Constant. 47, Grey, and Diana interrogate the Constant, pointing out that by being captured, his life is forfeit to the Partners. Defeated, the Constant reveals that Providence is made up of the Ingram, Carlisle, and Stuyvesant families, with each family having a representative that serves as a "Partner."
As 47 and Grey head out to confront the three families, the Constant taunts Diana about what she does not know about Agent 47. A final flashback reveals that 47 was responsible for the car bomb that killed Diana's parents.
Chapter 7: Golden Handshake
With the Constant's intel on Providence, 47 and Grey begin their mission to locate the three "Partners" until Diana gives them an update. She tells them that Hall found recent obituaries for all three of them, and the group concludes that the Partners faked their deaths and plan on resuming their lives under new identities. The Constant, seemingly unaware of this contingency plan, tells 47 and Grey to follow their bank accounts, which leads the two to Milton-Fitzpatrick Bank in New York. New data regarding the Partners is uploaded remotely to the bank, but 47 and the group have a limited opportunity to gather that information. 47 must also eliminate Athena Savalas, the bank's director and a Providence operative, in order to contain the data breach without the Partners finding out.
To retrieve the data, 47 can either infiltrate the vault and retrieve a data core or he can retrieve three backup data disks carried by Savalas and her subordinates: Fabian Mann and Mateo Perez. Once 47 has completed the objectives, he meets Grey outside the bank. Grey says that Hall found something interesting and that he will tell 47 on the way. When 47 asks where they are traveling, he replies "to paradise.”
