In the 100th episode, Bones looks back at the first time Booth and Brennan worked on a case together. The formation and evolution of their relationship, as well as the relationships of the other Jeffersonian workers, is examined.

Struggling to keep their tribe intact, the "Heroes" vow to work together as long as it takes to ensure that they outlast the "Villains". Meanwhile, the "Villains" begin to turn on one another after one tribe member makes a costly mistake at the Reward Challenge.

After confessing a long-lived love for catfish, host Alton Brown sets out to modernize its image.

Mark and Vogel execute a plan to uncover the identity of the mole in the FBI; Mark moves out of the house to protect his family; Keiko continues her search for Bryce.

When Stefan and Damon make a dangerous new enemy, Stefan suddenly finds himself in a perilous situation. Damon and Elena try to convince Alaric to work with them to help Stefan. Matt is hopeful that his mom, Kelly, may be back to stay. After her car breaks down in a storm, Caroline make a horrific discovery that shocks everyone in town.

When the CSI team investigates the brutal murder of a family, they trace the killer to the house next door, which might belong to the "Dr. Jekyll" serial killer.

Sam and Dean are outnumbered by demons, but are saved at the last minute by Rob and his townspeople, who are aware of the Apocalypse, and have been training to fight and kill demons. The small town is very religious and Sam and Dean meet Pastor Gideon, who introduces them to his daughter Leah, whom he claims is a prophet. Leah tells the townspeople they must obey her orders if they want a spot in Heaven but when she starts turning the townspeople against each other in the name of the Lord, the brothers realize they must kill her.

When a perfectly healthy woman is found dead from a disease she never had, the Fringe team investigates the origin of this inexplicably fatal condition before it claims more innocent victims. Meanwhile, Olivia struggles to keep Walter's secret from Peter, and her loyalty to Peter is tested as time goes on.

It'll be like a three-ring circus when the designers create garb as inspired by the big top. The stakes are high, too: The challenge determines which clothiers will advance to Fashion Week.

When a Jane Doe covered in blood walks up to Van Pelt and Cho it's up to Patrick Jane to try and find out who she is and what happened to her.

Guest: Author David Remnick talks about his new book The Unforgiving Minute: A Soldier's Education.

Neil DeGrasse Tyson

Demi Moore; Congressman Barney Frank; Train performs.

Sarah repeatedly gets into pedophiles' vans and discovers that it's the vans that are making the drivers creepy. Brian and Steve argue about whose turn it is to do the laundry after both are sprayed by a skunk.

The Important Thing discussed in this episode is the Important Thing of Space.

A human hand is discovered by DC Chris Skelton as he opens the post leading to Gene and the team investigating a murder. Alex and the team learn there have been several single women murdered across the country, each of them left with the same burn on them. They also learn that all the dead women where members of the Crescent Moon Dating Agency. Alex decides to join the agency so she can find out more and ends up organising a speed dating night.