In the new episode “Tradition!,” Robin (Sarah Wayne Callies) gamely makes an attempt to mark the fall holidays, knowing that she can’t hope to compete with memories of how Scott used to handle everything. Oliver (J. August Richards) struggles to come to terms with Peter’s (guest star Kevin Daniels) transgression, and Luly (Michele Weaver) gets some news about her adoptive family. Meanwhile, Theo (EmJay Anthony) makes some new friends, but soon finds they’re a dubious influence. Becky Ann Baker also guest stars.
The new episode “Revisited: Helping One of Our Own” finds host Robert Irvine back in Escondido, Calif., a year after he visited that community with his team to help Kaitlyn, the owner of Rose’s Cafe. In the months since then, however, Kaitlyn suffered another catastrophe in the form of a near-fatal car accident. Now Robert has returned to pull together a major event he hopes will help Kaitlyn with her mounting medical bills.
Jackie (Pauley Perrette) is taken aback when her ex-husband, Barry (guest star Kyle Bornheimer), unexpectedly shows up for a visit, but she quickly pulls herself together, realizing this development could give her an opportunity to gain full custody of Sammy (Antonio Corbo) in the new episode “Barry’s Back.” Elsewhere, Javier (Jaime Camil) struggles to find a truly meaningful birthday gift for his father. Natasha Leggero and Izzy Diaz co-star.
In the Season 3 finale, “The Toll of the Sea,” in a desperate gambit to save Hope, Ryn and Ben (Eline Powell, Alex Roe) confront their nemesis Tia (Tiffany Lonsdale) in a high-stakes undersea battle between the mermaid tribes. Elsewhere, Maddie and Robb (Fola Evans-Akingbola, Deniz Akdeniz) desperately race to find a cure to save Xander (Ian Verdun), while Helen (Rena Owen) and the hybrids try to restore order. Ted (David Cubitt) struggles to accept his son’s reality.