For GTA Online players that are new to the game, the motives as to why the Madrazo Family decided to steal from El Rubio and his Cayo Perico paradise may be unclear. The main thing to know is that Martin Madrazo has an issue with Juan Strickler, aka El Rubio.
Players meet Miguel Madrazo; Martin's son and heir to the Mardrazo Cartel throne at the Music Locker. Players learn that El Rubio managed to get hold of "intel" regarding the Madrazo Cartel that is threatening to their family. Not only that, but Rubio threatens to leak sensitive Madrazo info to the DEA if their prices aren't negotiated.
The Madrazo-Rubio grudge in GTA Online
El Rubio has been supplying the Madrazo Drug Cartel for many years. He is considered the world's number one narcotrafficker in the GTA Online universe. GTA Online players meet El Rubio (real name Juan Strickler) when they arrive at Cayo Perico with English Dave, who also knows the real reason why players are on the island.
Miguel Madrazo told the GTA Online player that the Mardazo Family needs to get those files "by any means necessary" and has sent the player on this crusade.
GTA Online players are involved in this Madrazo grudge mission to seek revenge against the dangerous and arrogant El Rubio. It is the player's job to successfully steal back the Madrazo Files. Not to mention that GTA Online players can also line their pockets and duffel bags with gold, cash, drugs and artwork during the heist.
There are other "main objective" items available during the Cayo Perico Heist missions, such as the Panther Statue, or the bottle of Sinsimito Tequila. However, when the mission is done for the first time, the items to steal are the "Madrazo Files". These are the secret files located in El Rubio's underground safe, which GTA Online players must return to Miguel Madrazo.
The fate of the files
After the player has successfully escaped Cayo Perico with the Madrazo Files, they meet Miguel Madrazo and his mother at their mansion in Los Santos. The final cutscene shows Miguel Madrazo calling his father Martin to tell him the job is done, desperate to impress.
The funniest part of this final cutscene is when Miguel realizes that some of the "intel" that was so important was evidence of Patricia Madrazo's affair with Trevor in GTA 5. He burns the files after speaking to Martin and GTA Online players can catch a glimpse of a photo showing a "loving embrace" between Patricia Madrazo and Trevor Phillips.
After GTA Online players complete the heist for the first time, Miguel suggests hitting Cayo Perico as many times as they want. This is when the item changes from the Mardazo Files to one of the alternate main objectives in the heist.
Encouraging GTA Online players to keep robbing El Rubio to teach him a lesson, the Madrazo Cartel is now vindicated and GTA Online players have a new strong ally in the Madrazo Family.