Leah breaks down when a doctor's visit reveals that there's something wrong with one of the twins and she turns to Corey for comfort, while Chelsea starts hanging out with her ex-boyfriend Adam again, much to her friends' dismay. Kailyn starts dating a new guy but things go haywire when Jo and his family find out about it, and Jenelle convinces her mom to let her come home when she realizes how much she misses Jace.

Over the fourth of July, Jo's parents give Kailyn an ultimatum; lose the new guy and focus on school or find a new place to live, while Jenelle has a change of heart and agrees to sign custody of Jace over to her mom. Leah and Corey give it another shot and get back together and Chelsea tells Megan she's giving Adam another chance.

Teenage mom Kailyn is forced to borrow money from Jo to make her school payments, and Chelsea breaks the news to Megan that she's going to let Adam move in with them so Aubree can have a normal family. Jenelle meets a new guy and stays out all night with him, and Leah and Corey decide to move in together and find their own place.

While Jenelle is trying to figure out how to pay for school, she breaks Barbara's rules again, and things get tough for Corey and Leah once she's stuck at home watching the girls full time. Adam moves in and Chelsea tries to keep it from her dad, and Kailyn starts school but has to figure out where she and Isaac should live when Jo's parents kick them out.

Things between Adam and Megan reach a boiling point and he forces her to move out, while Barbara helps Jenelle get her financial aid and invites her to attend Jace's first birthday. Things improve between Leah and Corey and their romance heats up, and Kailyn moves back in with Jo's parents and tells everyone that she doesn't want to be with Jo.

Corey surprises Leah with a marriage proposal, but things get hard when an eye doctor tells her Ali's development problems may originate in the brain. Chelsea tries to shift her focus back to school, while Kailyn gets a second job so she can move out on her own. Jenelle and her boyfriend Kieffer wear out their welcome at a friend's house and have to find a place to live while Jenelle begins college.

Jenelle and Kieffer are forced to ask Barbara if they can move in with her, while Chelsea's dad continues to put pressure on Adam to find a job. Kailyn starts dating her ex without telling Jo, and Leah and Corey put wedding planning on hold as the try to get some answers by bringing Ali in for an MRI.

Jo confronts Kailyn about dating Jordan behind his back and she moves in with her mom, while Leah and Corey continue planning for their wedding and get some good news regarding Ali's health. Jenelle and Kieffer hatch a plan to run off to New Jersey, and things between Chelsea and Adam continue to go downhill.

Things between Leah and Corey turn ugly when she starts having second thoughts about the wedding, while Chelsea and her girlfriends decide to celebrate her breakup with Adam by taking a road trip to a Lady Gaga show. Jenelle and Kieffer enjoy themselves in New Jersey until Barbara discovers her credit cards are missing, and Kailyn settles into life at her mom's house but can't get her belongings back from Jo.

Chelsea is busy studying for her GED, but gets distracted when she meets a new guy, while Jenelle has to face the music about stealing her mom's credit cards. Kailyn tries to focus on college and files for an official custody agreement with Jo, and Leah and Corey get closer when told they have to take Ali to another doctor days before their wedding

As Chelsea prepares for Aubree's first birthday party, her dad does what he can to keep Adam permanently out of the picture, while Jenelle is arrested for breaking and entering and realizes Kieffer is a bad influence. Kailyn goes to court to sign a joint custody agreement, and Leah and Corey tie the knot.

Jenelle is back with Kieffer after bailing him out of jail; Chelsea debates giving Adam another chance; Leah looks for a job; and Kailyn takes Isaac trick-or-treating.

Jenelle is living in her car with Kieffer; Leah is devastated to learn Ali will have to be sedated for an MRI; Chelsea re-tears her ACL; and Kailyn can't afford to live on her own.

Kailyn moves out without telling her mom. Jenelle files charges against Kieffer. Chelsea relies on Adam to take care of Aubree while she recovers from surgery. Corey and Leah get emotional during Ali's MRI.

Ali's MRI comes back negative to the relief of Leah. Jenelle juggles finding peace with her mom and dealing with Kieffer's domestic charges. Kailyn tries a new form of birth control. Chelsea fends for herself after surgery.

Kailyn adjusts to being alone for the holidays, while Chelsea and Adam reconcile. Leah works to make a memorable Christmas for the twins and Jenelle regrets filing charges against Kieffer.

Chelsea learns a friend of hers is pregnant, while Leah is horrified to learn that Aliannah may have a genetic disorder. Kieffer and Jenelle have a court date set for them and Kailyn becomes annoyed with the men in her life.

Kieffer is upset that Jenelle hung out with an old boyfriend. Leah is relieved that Ali has no major genetic disorder. Adam slips back into his old ways, much to the dismay of Chelsea. Kailyn considers filing for child support.

Jenelle moves in with her best friend Tori after fighting with Barbara, and Kieffer reenters the picture. Chelsea's relationship with Adam is going downhill fast. Ali may still have a genetic problem. Jo confronts Kailyn about filing for child support and they get into a big argument about who is the more responsible parent.

Jenelle fights with both Kieffer and Tori. Chelsea struggles to deal with Adam breaking up with her. Leah is livid when Corey wants to buy a truck instead of moving. Jo appeals Kailyn's child support request.

Kailyn's child support hearing is postponed and Jo meets Jordan for the first time. Jenelle has her day in court for the breaking and entering and possession of marijuana charges. Chelsea struggles to get over Adam. Corey finds out that Leah cheated on him two weeks before their wedding.

Jenelle decides to go to rehab. Chelsea finds a GED class at a local college, goes in for a consultation, and takes her first practice test. Leah files for divorce in order to protect her custody rights. Jo visits Issac during the week and Kailyn hooks up with Jo, even though she's still with Jordan.

Corey arranges visitation with the girls while Leah moves her stuff out of Corey's house. Jenelle finds out she might be bipolar while in rehab. Chelsea decides to take the GED test. Kailyn confesses her hook up with Jo.

In the Season 3 premiere, Leah prepares for her divorce; Jenelle tries to stay clean while on probation; and Kailyn wants to get back together with Jo.

Leah and Corey go to mediation over custody of the girls, while Chelsea and Adam take a big step forward. Jenelle fails a drug test, and Kailyn tries to connect with her estranged mother.