Four new "16 & Pregnant" alums are introduced in the "Teen Mom 2" premiere. The cast includes Jenelle, who is battling her own mother for custody of her baby; Leah, who has twins; Chelsea, who's determined to graduate high school while balancing the responsibilities of motherhood; and Kailyn, who's struggling to get over a breakup.
Tensions flare between Adam and Megan, prompting her to move out; Jenelle invites Barbara to Jace's first birthday celebration; Kailyn moves back in with Jo's family; and the romance heats up between Leah and Corey.
Kailyn starts dating her ex, but doesn't tell Jo; Leah and Corey bring Ali in for an MRI; Jenelle and Kieffer ask Jenelle's mom if they can move in with her; Chelsea's dad pressures Adam to find a job.
Kailyn moves in with her mom; Leah and Corey plan their wedding and get good news concerning Ali's health; Chelsea and Adam hit a rough patch in their relationship; Jenelle and Kieffer plan to move to New Jersey.
Chelsea tries to study for her GED, but a new boy becomes a distraction; Jenelle lands in hot water for taking her mother's credit cards; Kailyn files for a custody agreement with Jo; and Leah and Corey grow closer.