If you’re an avowed fan of the 2005 space western film “Serenity,” then you should definitely download Serenity Volume 1: Those Left Behind.

Developed by Dark Horse Comics, Serenity Volume 1: Those Left Behind is the comic prequel to “Serenity,” which itself is the feature film sequel to the short-lived yet cult-beloved TV series “Firefly.”

“Firefly” and “Serenity” originated from the mind of Joss Whedon, the creator of “Buffy the Vampire Slayer” and, more recently, the director of “The Avengers.”

For Serenity Volume 1: Those Left Behind, which is essentially a “midquel” of “Firefly” and “Serenity,” Whedon collaborated on the writing with Brett Matthews. A worthy collaborator, to say the least, since Matthews himself wrote several episodes of “Firefly.”

Serenity Volume 1 Those Left Behind

Serenity Volume 1: Those Left Behind, which unfolds through penciller Will Conrad and colorist Laura Martin’s impressively detailed comic artwork, sees the ragtag crew of the titular spaceship on a scavenger mission. Hoping to earn enough fast case to disappear for a while, they soon find themselves in the clutches of an old enemy, who engineered the mission itself.

Compatible with iPhone, iPod touch, and iPad running iOS 3.0 or later, Serenity Volume 1: Those Left Behind is available now in the App Store for $5.99.

Serenity Volume 1: Those Left Behind is actually also available in the App Store in three separate installments, each costing $1.99: Serenity: Those Left Behind #1 of 3, Serenity: Those Left Behind #2 of 3, and Serenity: Those Left Behind #3 of 3.