Justin and Riley’s relationship is put to the test after a spontaneous wedding goes awry and Billie makes a daring decision that could risk a prestigious internship that awaits her in the city. Meanwhile, Maisy reckons with life-changing news about an old enemy: her mother, Mimsy.

An opportunity arises for Justin to redeem himself when he discovers the Boathouse fire may have been the result of foul play. Meanwhile, Billie’s eco-ideals are challenged by a magnetic nemesis and Maisy tries to prove her mother is lying about her imminent death.

Maisy uses the anniversary of Derrick’s death to get Mimsy to confess to burning down the Boathouse with Justin’s help. Desperate for any opportunity to avoid her sibling love triangle, Billie agrees to go to Derrick’s anniversary dinner in exchange for Justin promising to get her a job from Maisy.

Justin and Billie trap all the suspects on a pontoon boat to clear his name by exposing the identity of the Boathouse arsonist. Keen to get to the tree planter’s farewell party before Ivy and Forrest leave, Billie agrees to help Justin. Maisy finally accepts her mother’s diganosis and decides to make peace before the summer ends.