In This Episode...
Mr. Harris, the chemistry teacher, is talking to a shadowy monster, presumably the alpha. He is frightened. Derek comes in and rescues Harris. The police show up, too, which leads to a big chase scene: Derek on foot, being chased by the police, watched (then fired upon) by the Argents, and followed by Scott and Stiles in Derek's car. Derek fills them in: Harris had in his possession what his sister was "working on" before her death...
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