Watch Birthday Bash for Free: How to Stream the Movie Online at 123Movies. . It's 1987, and Kristin is the new girl in town. With the insistence of her cousin, Natalie, Kristin is swayed to attend the birthday party of Jennifer- the most popular girl in school. But tonight, high school reputations are the least of their worries. With recent news of a homicidal maniac escaping a nearby hospital, party guests begin to disappear one by one.