-Anne Cardinal dies after being dumped at a hospital with a large gash on her face, looking like it'd been made by a claw.

-Anne was an evolutionary biology major who was searching for Big Foot. Castle is convinced that Big Foot killed her. 

-Turns out Anne was investigation the death of her college roommate Janine whose boyfriend Kurt fled to live in the woods. Anne's own video footage shows she was killed in the same forest.

-When Castle and Beckett got to check it out, then end up falling into trap. Beckett is able to climb out of the large hole in the ground on Castle's shoulders and goes to get a rope. When she comes back she finds Big Foot staring down at Castle.

-When she pulls her gun, Big Foot falls into the pit, startling Castle but it turns out to be Dr. Meeks, the foremost authority on Big Foot who wore the custom hoping to follow in Anne's tracks and find the real Big Foot.

-Ryan and Esposito find Kurt and bring him in for questioning. He says Janine was scared of someone and was leaving transferring to another school. Also, that her killer stole her special pendant. The same pendant was found in Anne's stomach.

-DNA evidence on the bloody club found in the woods shows that Anne's former professor murdered her when she threatened to expose his harassment. 

-At the loft, Castle sets a trap to find out who is stealing food from his refrigerator. Alexis gets a face full of blue dye when she sneaks in to take food back to her dorm.

-Turns out Alexis invested her allowance in a friends project to plant bamboo on rooftops to help clean the air. She didn't want a lecture from her father about being taken advantage of but realized too late she shouldn't have given her entire allowance. 

-Castle takes her out to dinner and offers to meet her friend and hear about his project.