Kiera and Carlos, reeling from a shocking loss, hunt down a ring of enigmatic high-tech thieves, even as a handsome, yet distant amnesiac begs for help in discovering his identity.

Sarah joins forces with an unlikely and untrustworthy ally, following a trail of clues that she hopes will lead her to the origins of the clone experiment. Cosima and Delphine make a discovery that could prove to be the key to treating her illness. Alison finds herself in unsavory company at rehab.

Sarah joins forces with an unlikely and untrustworthy ally, following a trail of clues that she hopes will lead her to the origins of the clone experiment. Cosima and Delphine make a discovery that could prove to be the key to treating her illness. Alison finds herself in unsavory company at rehab.

Murphy returns to camp claiming to have been held captive and tortured by the Grounders, and Clarke and Bellamy have very different opinions on how to handle his return. Octavia sneaks away to find Lincoln and returns with a serious warning for the 100. Meanwhile, a mysterious virus strikes camp forcing many to be quarantined, and Jasper pulls off a heroic move.

Murphy returns to camp claiming to have been held captive and tortured by the Grounders, and Clarke and Bellamy have very different opinions on how to handle his return. Octavia sneaks away to find Lincoln and returns with a serious warning for the 100. Meanwhile, a mysterious virus strikes camp forcing many to be quarantined, and Jasper pulls off a heroic move.

The wedding day chaos continues as the entire party shifts from one contingency plan to another. Guests start to get testy, Mitchell and Cameron are feeling discouraged, and poor Claire shows physical wear and tear.

The wedding day chaos continues as the entire party shifts from one contingency plan to another. Guests start to get testy, Mitchell and Cameron are feeling discouraged, and poor Claire shows physical wear and tear.

Sue looks forward to the trip to Walt Disney World; Brick begs his parents to take him to meet his online girlfriend; Axl waits to learn his final grades.

A series of unfortunate events threaten to spoil the trip to Walt Disney World.

A series of unfortunate events threaten to spoil the trip to Walt Disney World.