( I suggest reading My book NOELLA first before reading APOLLO , it's ok if you don't . But for background information on the characters and a few plot lines I think it will be helpful . ) Apollo , the twenty one year old heir to the Mexican mafia . His mother Noella Moretti-Garcia-Petrova is the current Donna to the Mexican mafia . His adoptive father Luka Petrova is the don to the Russian Mafia . Apollo was born prematurely to his very young and abused mother only she had no idea he was alive. Apollo's biological father Tobias Galanis who was the don of the Greek mafia hid Apollo on an island with the rest of his soldiers. But Apollo Wasn't alone , his mothers best friend and his adoptive fathers younger brother Ivan Petrova was also being held on the island along side his daughter Katerina Petrova . Katerina , was born due to Tobias Galanis forcing a woman to sexually assault her father Ivan to create a second in command for Apollo when he took over as don of the Greek mafia as an adult . Only Kat was born a girl , so Galanis decided she'd be better served as his wife then a second in command. Galanis forced Ivan with the threat of killing Katerina if he denied , to sign a marriage contract between her and Apollo with the official registry that upholds all contracts signed in the underworld. Growing up Apollo and Katerina were inseparable, best friends . The pair were equally obsessed and possessive with each other . When the pair learned of the contract they were both happy to know they would spend the rest of their lives together. Now Katerina is days away from Turing eighteen and marrying the boy she has loved her whole life . The pair also decided to wait until they were married to act on their romantic feelings and remain only friends during their childhood and teen years . So read along as the couple gets married , goes to College , trains to take over a mafia and becoming a doctor all while falling deeper in love.