GOLD DIGGERS: Mateo showed up on Carmen's doorstep after he heard his sister was married to a Rockwell. Turns out, they came from a very poor family and he wanted in on the new money that Carmen was getting. He asked his sister if she signed a prenup; she said no. He told her that they would have to come up with a backup plan incase her marriage to Mac failed. She agreed. Later, Mateo met Houston who offered him a job. Mateo accepted, wanting more money. Mateo befriended Grant, as Houston wanted to create chaos in Lex's personal life so he could take over as CEO of Blackmore Ltd. Mateo and Grant soon hit the sheets! Afterwards, Lex saw Mateo and Grant kissing and dumped Grant. Grant overheard Mateo tell Houston that their plan worked like a charm!

WALKING DEAD: Mateo learned from Carmen that she was suffering from nightmares since she killed Celeste. He encouraged his sister to move on because she is living the golden life. Carmen said she would try. Mateo, meanwhile, got a job as a stock boy at the hospital. Lex ran into him while he was visiting Stacey and Mateo apologized to him for working with Houston in breaking him and Grant up. Lex and Mateo struggled with their attraction. Shortly after, Lex proposed that Mateo could make it up to him by helping him with something. To help get Mateo to agree, Lex offered him money. Mateo agreed. Soon after, the two of them hit the sheets! Shortly after, Mateo told Lex that he changed Stacey's paternity test results like Lex wanted. They continued to sleep together. Later, Carmen called Mateo after she hit Mac in the head with a lamp after seeing the "ghost" of Celeste. Mateo pronounced Mac dead to a shocked Carmen. Mateo suggested that they tell the truth but Carmen reminded him that Lydia and Lucinda think she's a gold digger and they would use this as proof that she was after the Rockwell mansion. They agreed to bury the body on the estate of the Rockwell mansion until they could figure out what to actually do with the body and come up with the cover story. After they buried him, Mac's hand shot up through the grave, showing signs of life still!

CHRISTMAS SPECIAL: Mateo continued to encourage Carmen to keep Mac's death a secret. They came up with a plan for Mac to die on a business trip; then, they would dig up his body and have it sent back home for the service.
Mateo and Lex, meanwhile, continued to grow closer and they slept
together on a regular basis. When it was time to dig up Mac's body,
Mateo and Carmen were horrified when the body was missing!

CABO WABO: Carmen and Mateo worried when they couldn't find Mac's body. Mateo convinced Carmen that Mac is still dead otherwise he would have turned up alive. He forged documents for Carmen to "prove" that Mac's body perished in the plane crash. The Rockwell's were crushed. Mateo and Lex, meanwhile, grew closer as they lived together now. They agreed to keep the family drama out of their relationship. The Rockwell's were further upset, however, when Mac's will left each Rockwell sibling and Carmen equal parts of his shares in Rockwell Mining. Lydia produced an amendment to the will confirming Mac wanted Lex to have all of his shares, meaning he would be the CEO of the company. Carmen asked Mateo for help so Mateo dragged Lex to Cabo claiming he wanted a retreat with his lover. Mateo convinced Lex to keep his phone and tablet in the hotel safe, knowing that Lex would otherwise find out how dire things were at Rockwell Mining. Mateo, shortly after, saw Lex trying to open the safe and realized that he had to stop him. He knocked him out and took him on a catamaran. Grant, however, knew what Mateo was up too and saved Lex. Mateo pulled a gun on the men but Lex fought with him over the weapon. A shot tired which hit one of the beams on the boat; the beam hit Mateo on the head, which caused him to fall into the ocean and die.

SEASON SIX: Mateo revealed himself to be alive as he survived the boat accident in Cabo. He was back because he wanted to get revenge on Lex for trying to kill him. He started making Lex think he was crazy by turning the water on Lex's shower; having water based footprints at the Blackmore Ltd. office and having more water in the office. Mateo, then, revealed himself to Carmen, who agreed to help her brother with his plan. Mateo suggested to his sister that she marry Slate so they could have access to the Rockwell fortune if they needed it. Mateo, meanwhile, continued to blackmail Quinn into helping him brainwash Lex by threatening to reveal the true identity of her unborn child's father. Quinn planed a device in Lex's office that made Lex hear Mateo's voice. Soon, Lex fell into a spell and knocked Houston out. Mateo had Lex take Houston to a boat, where he tied Houston up. Mateo wanted Lex to kill Houston, so he would go to jail. Stacey, Quinn and Kent arrived to save Lex and Houston. Carmen pulled a gun on them; she and Stacey fought for the gun, which fired and hit Mateo, who died from his injuries.