Thriller Idea

After a long time considering what would work and what would be effective in a thriller. I finally decided on the story line of a young girl, 18-years old, who is quite innocent and shy. She gets mixed up with two other girls who are very rowdy and outgoing. On her 18th birthday her two friends convince her to come out for a drink at a bar, she is clearly uncomfortable with the idea so on the night she drinks quite a bit so she is relaxed. But she gets her drink spiked and ends up in a coma in hospital. It is up to her two other friends to figure out who spiked her drink, and what she was spiked with. They have to put themselves in dangerous and risky situations in order to solve the mystery.