GRIMSTONES

In nine chatty letters, young Martha Grimstone introduces her peculiar family, describes the creation and hatching of three-legged little brother Crumpet, and fervently urges readers to write back.

This epistolary narrative has been spun off from a puppet performance and comes with inset photos of Tim Burton–style papier-mâché puppets in elaborately crafted antique settings and animations that range from a circling ring of quail to words that drop to the bottom of the page with a crash. There are also several full-screen interludes in which Martha—moving and gesturing like a marionette—beckons eerily to viewers, dumps potion ingredients into a pot or has a tap-activated exchange with her alchemist grandfather Elcho. She chattily shares hopes and dreams (“You never know, one day I could be the Lady of the Strongest Intestines in the Whole World”) as well as a string of domestic disasters or oddball incidents. In doing so, she repeatedly invites her readers to respond. Responses might in fact be mandatory; in one setting, each letter after the first is locked until the day after an answering letter is composed on a preformatted "Write Back" page. This can be toggled so that Martha writes regardless of readers' correspondence habits. There is no audio narration, but the app is supplied with sound effects and an optional background piano track.

A pleasantly gothic pleaser for fans of Unfortunate Events.