Teen Mom 2 follows the lives of Jenelle, Chelsea, Kailyn and Leah who all featured on the second series of 16 and Pregnant, as they navigate the first years of motherhood while dealing with the challenges that all young people face. Season 1 Party-loving Jenelle struggles to step-up to the responsibilities of being a mum and makes the agonising decision to assign custody of baby Jace to her mum. As for Kailyn, her tempestuous relationship with her baby's father, Jo, quickly crumbles, and with poor relations with her own family, she is forced to go it alone. Meanwhile, Chelsea is hopelessly in-love with bad-boy Adam, much to the disappointment of her overprotective father, while Leah's world falls apart when the past catches up with her, costing her the breakdown of her family unit. Season 2 After meeting boyfriend Kieffer, Jenelle's life has gone from bad-to-worse and this season Jenelle's reckless lifestyle catches up with her in a big way. As for Leah, baby Ali's health issues force her and Corey's relationship to reconcile, while Chelsea's life is made even more challenging when she breaks her ankle, forcing her to rely on Adam more than ever before. Meanwhile, Kailyn's relationship with Jordan starts to get serious, but one careless moment costs her everything… Season 3 Leah is forced to let go of Corey when her divorce is finalised, but she soon becomes entangled in a love-triangle when she starts a whirlwind romance with a new guy. Meanwhile, Jenelle battles to stay clean after rehab and embarks on a mission to find out who Jace's biological father is. As for Kailyn, she struggles to get over Isaac's father Jo, and in the process tries to rekindle things with her former lover Jordan, before meeting an unexpected new love. And finally, Chelsea and Adam try and take their relationship to the next-level when he gives her a promise ring, but their renewed honeymoon period is short-lived. Season 4 Seemingly back on a good path, Jenelle meets a new guy, Gary, but a dramatic fight brings their relationship to an abrupt end, sending Jenelle's world back into a downward spiral. After enduring a miscarriage, Leah's love-triangle starts all over when she begins to doubt her relationship with Jeremy, hooking back up with Corey, before returning to Jeremy! Meanwhile Kailyn moves in with Javi and her relations with her ex Jo, deteriorate when they have a violent altercation. And finally, Chelsea still struggles to move on from Adam, revealing to a friend that she may be pregnant again.