FIRST, Tyler called Bill Forbes to help him break the sire bond. The only way, according to Caroline's dad? Continue to turn on your own until it is pain free, thereby removing your subconscious gratitude to Klaus for ensuring you never NEED to experience that pain again. Tyler succeeded at this once, but he has a long way to go.
SECOND, Alaric learned Dr. Fell's secret, after Damon accused her of killing her ex-boyfriend and she responded by knocking him out with vervain and taking his blood. Turns out, she uses it to save patients who would otherwise die. Alaric responded to this by letting Dr. Fell in on all his secrets, including the supernatural ring. They kissed.
THIRD, Bonnie visited her mom for the first time in 15 years because she thought she could help her open the locked casket. But her powers were taken away after she left Mystic Falls long ago, following the entrapment of a vampire who came to town: Michael. She locked him in that tomb and escaped and enjoyed her new life.
But Klaus got a hybrid out to Abby Bennett's farm house, also and he compelled Jaime, a boy Abby took in many years ago... it was a long, complicated plan, but in the end, Klaus learned the location of the coffins. Fortunately, Damon got the locked one out in time and also undaggered one of Klaus' relatives: Elijah. He ended the episode by showing back up and killing a hybrid in front of Klaus.
Oh, and Elena told Stefan she and Damon kissed.
Source: TV Fanatic