Archer and his colleagues at ISIS voyage to the final frontier in an effort to prevent a catastrophe on the International Space Station.

Andre proposes that he and Shirley remarry and a wedding date is set. Britta and Annie get busy planning the wedding and Jeff prepares to give a wedding speech, while Troy and Abed get ready to be "normal" for the occasion. Meanwhile, Pierce and Shirley pitch a sandwich shop idea to Dean Pelton for the Greendale cafeteria.

Derek encourages a hesitant Meredith to work with him again in neurology; Jackson's mother, Catherine Avery, returns to Seattle Grace with a urology fellow and develops an interest in Richard; and Cristina becomes increasingly suspicious of Owen's every move. Meanwhile, Alex tries to deny the fact that Morgan may be falling for him.

Stephen is suspicious of geriatric jihadists, Rick Santorum speaks from his heart, and Dexter Filkins tells Stephen why we need other countries.

Andy makes a game-changing decision and takes a road-trip odyssey in the name of romance. Elsewhere, Nellie arrives at the Scranton branch and sets out to seize the manager position.

The present-day murders in Mystic Falls remind Damon of a similar crime spree a century earlier. In flashbacks to 1912, Damon recalls a beautiful vampire, Sage, who showed him a whole new way to exist. Sheriff Forbes warns Damon not to get involved in her investigation, but Damon is convinced she’s going after the wrong suspect. Elena and Matt resort to breaking and entering in their search for evidence to prove Dr. Fell is a murderer. For reasons known only to her, Rebekah, becomes interested in locating one of the town’s oldest landmarks. Finally, Elena comes to a new understanding of the path her life has taken, and Damon makes an emotional confession to Stefan.