Katherine "Katie" Embry is a supporting character in The Ring. She is also one of Samara Morgan's victims and is presumably the first to be killed by the cursed tape along with her boyfriend and her other few friends.
Her mysterious death is what initiates her aunt, who is also the main character of the movie, Rachel Keller to investigate the cursed tape and eventually, confronting the evil entity of Samara Morgan.
Katie is seen at the beginning of the movie and she is having a sleepover with her best friend Becca Kolter on one, rainy night. She is clearly intelligent since she discusses about how electromagnetic waves can be passed through people's head every second but this can also subtly hint Samara's power since she can "burn" images onto objects or into the minds of a person or an animal.
After Becca tells her that she has a better story, Becca tells her about an urban legend about a cursed tape which kills the viewer after 7 days. Frightened, Katie asks her how she knew the story since a week ago, Katie actually watched the cursed tape with her boyfriend and her friends at Shelter Mountain Inn after they tried to record a football match and they thought the football match would appear on the screen. Becca thinks that Katie is trying to scare her but suddenly, Katie starts to choke but it was later revealed to be a pratical joke.
They both have a pillowfight and insult each other jokingly but suddenly, the phone downstairs began to ring. Becca soon realises that the cursed tape is no urban legend and nervously, they both go downstairs to pick up the phone. Having enough of Katie, Becca confidently picks up the phone and hands it over to Katie. The caller is revealed to be Katie's mum and they both have a quick chat and during their conversation, Katie pours herself a glass of lemon juice. Becca later goes upstairs to go to sleep.
Just before she is about to take a sip, the TV in the living room suddenly turns on by itself on static mode. Thinking that Becca is playing a prank on her, Katie turns off the TV with the remote immediately and after she is about to go upstairs, the TV suddenly turns on by itself again. Angrily, Katie plugs out the wires of the TV and while she is looking at her reflection on the TV screen, a fleeting shadow can be seen passing by the kitchen window, which frightens her.
Katie then sees the door of the refrigerator opening by itself and once again, she furiously shuts it tightly and calls for Becca upstairs. After no reponse, Katie quickly dashes upstairs but there is no-one there, except for a puddle of water leaking out of her bedroom. Realising Samara's presence, Katie opens her bedroom door and to her horror, she sees an image of a well on her TV screen and the image of the well is part of the cursed tape.
She screamed loudly on the top of her lungs but in the process, her face also discolours and distorts and this hints that Katie was already dying when she first saw the image of the well on the TV. Samara is not seen during this scene but it can implied that Samara already came out of the TV (hence the leaking puddle near the bedroom door), which scared Becca (while she was in the room when Katie was talking on the phone) so much that she had to institutionalised and Samara waited for Katie to come upstairs to give her a grim surprise. Since Samara isn't seen in this scene, it can also be implied that this is her point of view, hence her abscene and Katie's face discolouring and distorting when she enters her room.
Katie ultimately dies of a heart attack and after her death, her body becomes bloated and rotten, her eyes are rolled backwards and her facial expressions when she first saw Samara was left frozen on her distorted face. Samara later drags her body into the closet and arranges her position in an organised fashion for other people to discover and to be left traumatised purposely, since Samara is an insane psychopath that loves to kill people and inflict pain.
Her mother later finds her body in the closet and to her shock and disbelief,asked her sister, Rachel Keller, to investigate the reason behind her mysterious death since the local doctors couldn't find the exact cause of death and simply stated that it was a heart attack despite Katie being a healthy teenager.
At Katie's funeral, Rachel asks Katie's remaining friends about the cursed tape and it is revealed that her friends that watched the cursed tape with her were also killed during the same time and night that Katie died. One of them states that Katie's boyfriend has supposedly killed himself by jumping off a building but in reality, he was presumably trying to escape from Samara Morgan while she was crawling out of the TV and fell off the building by accident when he tried to run away outside. Another theory states that Samara actually forced him to commit suicide with her powers that enabled her to burn "images" into other people's minds.
While rummaging through Katie's photos, she notices Shelter Mountain Inn in one of the photo's backgrounds and goes there to watch the cursed tape herself and to investigate the mystery behind it with the help of her ex-boyfriend Noah Clay and her intelligent, independent and psychic son Aiden.