Ep 16. Trajectory

Trajectory is the sixteenth episode of the second season of The Flash. The episode starts with Barry and the team trying to figure out who is the new speedster in town, named Trajectory, who has been causing havoc in Central City. Meanwhile, Caitlin and Jay are working together to find a way to restore Jay's powers, which have been lost due to Zoom's serum.

As Trajectory continues to cause destruction, the team realizes that she is using a special drug to enhance her speed. Barry decides to investigate the company that produces the drug, while Cisco works on a way to track Trajectory's movements.

Barry's investigation leads him to the company's CEO, who denies any involvement in the creation or distribution of the drug. However, Barry and Cisco discover that the CEO's research assistant, Eliza Harmon, has been stealing the drug and injecting herself with it to become Trajectory.

When confronted, Eliza reveals that she became addicted to the drug and was using her new powers for personal gain. However, the drug's effects are taking a toll on her physical and mental health, causing her to become increasingly unstable.

As Barry and the team try to stop Trajectory and find a way to help Eliza, they also have to deal with another problem: Wally West, Iris's long-lost brother who has recently come back into her life. Wally is a street racer and is determined to beat Trajectory's record-breaking speed, putting himself in danger in the process.

In the end, Barry confronts Trajectory and is able to stop her before she causes any more harm. Eliza, however, is unable to control the drug's effects and ends up dying as a result.

The episode ends with Caitlin and Jay making progress on restoring Jay's powers, while Barry and Iris have a heart-to-heart about their feelings for each other. It is also revealed that Zoom has been watching everything that has been happening in Central City, hinting at his further involvement in the show's upcoming episodes.