Plot

Natalie is an independent artist estranged from her father. Although her family owns the prominent Freeman Museum, she uses her late mother's maiden name to keep her identity a secret from everyone including her artist boyfriend, Alex. When Natalie's father dies, she takes on ownership of the museum with the help of her late father's assistant, Derrick. Natalie quickly learns that someone has been stealing paintings and replacing them with counterfeits. But due to the nature of her father's untimely death, Natalie realizes she's not the only one keeping secrets. In her search for the truth, Natalie encounters dangers that threaten not only the museum but her life as well. Could someone close to her be intent on destroying the museum?

It all started when Natalie was a little girl who loved drawing sunflowers. Her parents were the owners and curators of an art museum, and in the wake of Natalie's mother's death, her father was managing it all alone as best he could. Natalie meets a boy named Derek, who is there with his father, waiting to see if their painting is on exhibit. Sadly, Natalie's mother did not keep a proper record of the painting, and it is not in the museum. As an artist, Stephen is offended and feels betrayed that his work has been lost or neglected this way. As he stomps out of the museum in anger, vowing to destroy the place, he gets into a car accident, which is witnessed by his son, Derek.

Years later, Natalie is living with a different surname since she has grown apart from her father, who was always too busy with his work. She is seeing someone named Alex, and he doesn't know that she is a Freeman since Natalie has told everyone that her last name is Calvert. But the secret comes tumbling out when Natalie gets a call that her father has had a heart attack, and she needs to visit him. When Natalie goes back, she is not in touch with her friends for a while. They still don't know that she is a Freeman, and since she has lied about her real identity, she cannot constantly keep in touch with them without coming across as disingenuous.

As Natalie takes care of her father, they reconnect once again. Robert admits to Natalie that after her mother passed away, he did not know how to be there for his daughter, and his only solace was his work, which he completely threw himself into. As for Natalie, she felt the distance grow between her and her father, and when the time came for her to go to college, she never looked back. One of the reasons Natalie went by a different name is because her area of interest and work is the arts. She wanted to make a name for herself, independent of her family's legacy, and she also wanted to have friends who would see her for who she was. But the entire plan has changed since Robert's heart attack.

During an exhibition, Robert is informed by a woman, Danielle, that one of his paintings is a fake. Robert is shocked since that painting was his wife's favorite and has never been loaned out to anyone. Dannielle is sure about her conclusion since she appraised the original a few weeks ago for someone else. A concerned Robert takes down the painting, and that night, he has another heart attack, but before he can take the medicine in his pendant or call for anyone, someone takes away that chain for him, leaving the old man out to die. Robert passes away, and everyone thinks it is because of natural causes. Nobody suspects foul play, though Natalie is concerned that they cannot find the pendant anywhere.

Meanwhile, an article comes out in the newspaper about Robert Freeman's death, and it has a picture of him and Natalie together. Alex and his friends see this, and they finally come to know who Natalie really is. While the others are able to get over their feelings of betrayal, Alex is not. Other than the fact that his feelings for Natalie ran a lot deeper than the others, he also has a past where his father struggled his entire life because he was never acknowledged by people like the Freemans. That has caused Alex to have an aversion to them, and he cannot accept one of them as the love of his life. That is why he is so against showing them his paintings.

Back in the museum, Natalie learns about the forgery, and she also deduces that there are other fakes in the place. That is when she comes across a painting left there by an anonymous woman, and when Natalie takes a closer look at it, she finds Alex's signature. She meets up with the woman, Harper, to find out more, but she comes to know that Alex just wants his painting back. Natalie follows Harper home, where she confronts Alex about so many of the paintings in her museum being fakes that he has painted. That is when Alex reveals that he made those paintings for a private collector, who said that he couldn't afford the real thing. It was just Alex's way of earning some extra money, and he wasn't aware that they were being used for such purposes.

Natalie has started to understand that things aren't as simple as they look. She is especially curious as to what could have happened on the night of her father's death, and she asks her security, Tina, to get her the footage of the CCTV outside Robert's office. Tina is dating Derek, and he asks her to come up to the roof to see the stars with him, but thankfully, before Tina goes there, she checks out the footage and finds that it is Derek who is responsible for killing Robert. She sneaks into his office, and just then, Derek also arrives there and shows her the pendant. He admits to killing Robert, and he also pushes Tina off the roof, thereby thinking that he has erased all evidence of his crime. He places the pendant in her hand and writes a fake note where she apologizes to Natalie for everything. This makes it look like Tina was the one dealing with the forgeries, and she committed suicide when her crime was caught. That would have been it, but luckily, Tina had sent the CCTV footage to Natalie right before she died. When Natalie sees that, she realizes what must have happened. During this time, Derek also tries to kill Alex, who has come to meet him, and he knocks him down. Natalie arrives there just in time and is able to take down Derek at the end of Secrets at the Museum. Alex is alive, and Derek is arrested. He was taking revenge for what had happened to his father all those years ago and was working to destroy the reputation of the museum, but Natalie caught him in time.

In Secrets at the Museum's ending scene, we see that Alex and his friends' art gets its due recognition through the museum, and even Alex's father's painting finds a notable place there. In the end, it was all about giving art the value it deserved. (thanks to dmtalkies)