Gregory Michael

Ted, Marshall and Barney embark on another "trilogy time," where they get together every three years to watch the "Star Wars" trilogy and envision what their lives will be like in another three years. Meanwhile Barney and Quinn move in together.

Rusty prepares for his first date with Jordan, but due to a series of events, Casey ends up tagging along. Cappie and Evan must each reveal a secret.

It’s the day after the End of the World party which has changed some people’s lives dramatically. Max has gone back to England since Casey broke his heart, so Rusty has no one to talk to about his choice to go to the party over finishing his Chemistry project. He tries to get into the lab but finds it locked. Jordan implores Casey to help Rusty who is now failing the Honors Program. Casey, still hurt from her encounter with Cappie at the party, agrees to take charge and help her brother. When they try to get into the lab, Cappie shows up also intending to help Rusty. The three awkwardly get the project done but not without confronting each other about what really happened the night before and what it means for Casey and Cappie. Rebecca is mysterious about hooking up with a guy at the previous night’s party, and offers to pay Evan if he will pretend to be that guy. The Omega Chi’s throw a Dead Man’s party to celebrate the start of the Gotcha! Game, and Evan has to endure being Rebecca’s new boyfriend until she shocks everyone with a “breakup”. Calvin thinks he slept with Grant, but finds out they just kissed while Dale slept with Sheila and is extremely upset about losing his virginity. When Casey and Cappie have a moment on campus where she shoots him as part of Gotcha!, he flashes back to the End of the World party when Evan talks him out of chasing after Casey explaining they’re just not right for her.

Casey and Cappie decide to tell people about their new relationship, and worry about how people may react. Ashleigh is excited but has her reservations since it took Cappie so long to realize what he wants with Casey. Evan doesn't seem to take the news of Cappie and Casey as well as he plays off, and OX playing a huge prank on the KTs adds to the problem. Casey talks Cappie and Evan into joining the KTs and OXs together for the ultimate prank – getting Officer Huck. They decide to drop Huck’s golf cart off a roof, but in the middle of the prank the OXs (including Evan) abandon the prank, leaving some of the KTs to take the heat which ends up being expulsion. The ZBZ girls prepare for Song Fest, which is their way back to the top of the Greek ladder. Katherine tells Beth she can’t take part since she deactivated to become an IKI, so ZBZ is down a girl and a choreographer - meaning they need a new dance entirely. Katherine also offers Casey a board position but tells her she can’t compete in Song Fest if she accepts the job. Casey decides to stick with her house, and the girls perform an amazing number yet strangely lose to the Gamma Psi’s mediocre performance. They realize something is off and sneak into the Gamma Psi house to find clues, but end up leaving a candle burning and setting the Gamma Psi house on fire! Rusty and Dale are still upset about fighting over the science grant they both want. When they gather to hear the final winner it?s announced that, since it was such a close race, winners won’t be decided until next semester. Calvin talks them into trying to deal with their issues as tensions continue to rise. Rusty and Dale think it’s a great idea and decide the best way to do that is a Battle-Bot Royale! During the battle of their homemade robots Dale starts to lose. Calvin tries to get Rusty to realize that Dale needs this win more than him. Rusty has to make a decision to back down to be a best friend instead of the best competitor.

The fallout from the float prank leads the Kappa Tau house to plan an "End of the World" party - which leads to revelations from everyone.