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.
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.
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; Martin, Arthur, Frank and Henry chase after the women.
Lisa's unexpected pregnancy is more complicated than Lena and Martin anticipated; Lena decides to help Lisa despite her not wanting them involved in the baby's life; Mae and Mason try to force Lena to admit that she and Martin are back together.
Martin grows suspicious of Lena's strange behavior when she begins sneaking out of the house to secretly help Lisa Apple with her baby; Martin takes Mae on a driving lesson.
Lena and Martin announce to the kids that Lisa Apple's baby is their half-sister; Mason overhears Lena and Martin's conversation about Lisa's financial difficulties and decides to start a fundraising campaign to help.
Lena and Martin plan a fun outing, only to be interrupted by a blackout; Lena urges Maya to get induced but must honor her birthing plan; Martin continues to try and figure out where his relationship with Lisa stands.
Milo complains that Grandparents Day is coming up at school and doesn't feel Henry is interesting enough to participate, so Lena and the kids urge Martin to reconnect with his long-estranged father.