Frazzled by her intimate dream about Martin, Lena accidentally injures her tooth and reluctantly goes to the dentist; Martin escorts Lena to Mae's parent-teacher conference after she inadvertently gets high; Maya asks a familiar face out on a date.

Vlad announces that construction on the house is almost finished; Martin begins dating a divorcee who works in his building; Camille tries to be a good influence on Arthur's nephew.

After a doctor's visit, Arthur learns he's under stress due to the approach of Valentine's Day; Arthur asks Camille if they can take a break from the holiday; Lena decides she wants to cook a platonic Valentine's Day dinner for Martin.

Lena confirms that she has feelings for Martin but is confused when his response is not what she expects. To escape the situation, Lena joins Camille and Maya on a road trip for a girl's weekend before Maya's baby arrives. Meanwhile, Martin, still considering how to respond to Lena, joins Arthur, Frank and Henry in chasing after the women.

Lisa's unexpected pregnancy causes more complications than what Lena and Martin anticipated. Without Martin's knowledge, Lena decides to help Lisa despite her insistence about not wanting them involved in the baby's life. Meanwhile, Mae and Mason try to force Lena to admit that she and Martin are back together. After Maya's false labor scare, she returns from the hospital and is put on bedrest by Frank who insists on taking care of her.

In an effort to connect with their kids and bring the family closer together, Lena and Martin plan a fun outing, only to be interrupted by a blackout. Elsewhere, Lena urges an overdue Maya to get induced but must succumb and honor her birthing plan. Meanwhile, Martin continues to try and figure out where his relationship with Lisa stands.

Lena tries to support Maya with her pregnancy, only to get accused of being too controlling; after Martin reads Mae's diary, he suspects that she is romantically involved with her teacher and panics.

Martin grows suspicious of Lena's strange behavior when she begins sneaking out of the house to secretly help Lisa Apple with her baby. Lena tries to avoid Martin but feels she needs to tell him the truth about her arrangement with Lisa. Meanwhile, Martin takes Mae on a driving lesson, which turns into a hot pursuit.

After Lena and Martin sleep together, Lena searches for signs that they are or aren't meant to be a couple; Arthur and Camille trail Lisa Apple, hoping to determine if she is pregnant with Martin's baby.

Things get complicated after Lena and Vlad kiss; Martin goes to Paige's house for more privacy but feels uneasy; Mae finds out that Mason has a crush on a girl at school.

Lena and Martin announce to the kids that Lisa Apple's baby, Annie, is their half-sister, and Martin is surprised when they aren't interested in meeting her. Lena feels the burden of being stuck in the middle between Martin and Lisa but still offers to help bring both families together. Meanwhile, Mason overhears Lena and Martin's conversation about Lisa's financial difficulties and decides to start a fundraising campaign to help. Elsewhere, Lena feels a bit of empty nest syndrome.

Martin finds every way he can to avoid asking Lisa Apple if she is pregnant; Lena worries Mason is changing himself to please his new girlfriend; Maya tells Frank a made-up story about a friend who is dating someone new.

Camille urges Lena to become more active on social media to get her business off the ground; Martin takes over for Lena as Milo's room parent and investigates why Milo is feared by his classmates.

Lena and Martin battle for control of the house; Milo announces he wants to go to a school for the gifted; Lena and Martin give conflicting advice to Mason on how to deal with his recent breakup.

Lena decides to call Martin's bluff on selling the house but is surprised when he begins getting the house ready for sale; Lena tries to cheer up Mae by inviting her friend from camp to visit; the friend seemingly brings supernatural events with her.

Lena and Martin have opposing mind-sets over the new contractor's repair methods; Martin takes Mason camping to help him get over his breakup with Hazel and to teach him how to be a man, but learns from him that it is okay to express his emotions.

Milo complains that Grandparents Day is coming up at school and doesn't feel Henry is interesting enough to participate. Lena and the kids urge Martin to reconnect with his long-estranged father, Brock, to rebuild their relationship. Meanwhile, Lisa continues to struggle financially and considers moving back home with her parents. Elsewhere, after listening to a true crime podcast, Maya worries that Frank has a dark past he has been hiding.

Lena tries to figure out if Mae is romantically involved with her new best friend; Martin worries about Mason's relationship with his new girlfriend.