Aired: April 17, 2011 | Season: 5 | Episode: 3

Overview
Runtime: 90m
Directed by: Charles Palmer
Written by: Colin Dexter
Guest stars: Alex MacQueen, Christina Cole, Douglas Henshall, Fiona Wade, Jack Roth, Lucy Liemann, Nichola Burley, Sam Hazeldine, Thomas Brodie-Sangster
Description
When a student is found dead during a college-based clinical trial for a new anti-depressant, Lewis and Hathaway struggle to determine whether the incident was murder or suicide, and receive little assistance from the institution's evasive psychiatric professor. A second student's death then leads to the revelation that the trial's participants are all operating under the influence of mind-altering drug ketamine, and that the lines between love, obsession and madness have become dangerously blurred.