It received positive reviews for its animation, acting, story, and soundtrack by Mark Mothersbaugh, as well as Cara's song, "I Choose".

The children follow a rainbow to the doorstep of Mr. Melanoff's candy factory, and believing it to be a suitable home, name the baby as Ruth and leave her there.

Linda proves to be much warmer, happy and more caring than the Willoughby parents, and Jane and the Barnabys warm up to her almost immediately; Tim, however, remains distrustful.

Melanoff explains that he originally intended to hand the baby over to the Department of Orphan Services, but grew attached to her; Linda is assured that Ruth will be well cared for in the factory.

Heartbroken by Tim's betrayal, Linda leaves in tears, and the Willoughby siblings are forcibly taken away and placed in separate foster homes until their parents return.

With the help of Linda, Ruth, and Melanoff, the Willoughbys build a dirigible to rescue them from the "Unclimbable Alps" in Switzerland (shown and pronounced as Sveetzerlünd), which is the final and deadliest destination on their parents' trip.

As they reach their destination, they follow a trail of their mother's yarn to the top of the mountain, where they find their parents nearly frozen to death.

Thankfully, Ruth, Melanoff, and Linda followed the dirigible and heard Jane's song, finding the siblings just in time.

In June 2017, the cast was expanded to include, Terry Crews, Maya Rudolph, Martin Short, Jane Krakowski, and Seán Cullen.

FX lead Helén Ahlberg created graphic compositions to carry the “once upon a time” tone that combines heightened textures, simple camera, lack of motion blur, and a strong depth of field to the film's stop motion-like style alongside the squash and stretch principles done by Maya's SyncSketch tool.

[7] The original song "I Choose" (performed by Alessia Cara, who plays the voice of Jane in the film) was released independently by Def Jam Recordings.

The site's critical consensus reads: "An appealing animated adventure whose silliness is anchored in genuine emotion, The Willoughbys offers fanciful fun the entire family can enjoy.

"[13] The Hollywood Reporter's David Rooney said that "the Netflix animated family comedy-adventure has an oddball charm that works surprisingly well.

The composer Mark Mothersbaugh contributes a jazzy score and original song (performed by Cara) that punctuate the giddy mood.