Mazda Hun is a soldier caught in a web of political and military struggles beyond his comprehension. Captured by the government, they sentence him to Lethe. Society doesn't believe in the death penalty anymore. They've modernized the paradigm of punishment.
Lethe has many names: mercy, treatment, repair, reformation and rehabilitation. Some even call it justice. The Lethe procedure inflicts no pain and is over quickly, but its victims consider it a fate worse than death.
Lethe is the execution of a person's soul. They make room for a new personality that will remember nothing of the old. Those who undergo the process don't seem quite human ever again. And Mazda Hun's time is running out fast.
Danica Davidson for Graphic Novel Reporter
Lethe starts with a prose preface to set up the science-fiction setting, then quickly launches itself into a visual representation of the story. In the future, humankind has destroyed earth's environment. Some people escape to other solar systems, but they don't live a peaceful, egalitarian existence. In this new version of humankind, there is something called Lethe, and Mazda Hun has been sentenced to it.
Lethe is a fancy way of saying execution. Except it is worse than an execution, and people sentenced to Lethe might plead to be killed instead. Lethe destroys the ego, the mind, the soul. With execution, only the body is destroyed. With Lethe, it's total erasure. Some people try to make it sound humane and better than execution. Mazda isn't fooled. He knows he's facing a terrible fate.
As an act of mercy, he is provided a counselor by the government to talk with him before his end comes. The counselor asks him to tell her about his past, so that she can store the memories that will be taken away from him. At first, Mazda resists, thinking it's useless, only to eventually give in to her request. From here we receive flashbacks and philosophical musings on the meaning of ego and existence. This is a perfect example to show people how serious and intellectual graphic novels can be. It's not the easiest read, but it's transfixing.
To be sure, Lethe is complex, fascinating, and very intense. Its feeling is existential and dark, but it's also compelling. While many graphic novels are done in black and white, Lethe is beautifully illustrated with water colors. Many images are surreal, going along with the book's stream-of-consciousness atmosphere. Some pages consist entirely of images to get the point across.
There's also quite a bit of mythology to be found here. Lethe comes from Greek mythology and is the name of the River of Forgetfulness. Other references to ancient Greece are frequent—Gorgonia, Achaea, Medusa, etc.—but there is also mention of the Norse goddess Hel. Mazda's name comes from the Persian god Ahura Mazda.
Lethe is aimed for 16+. However, because of its cerebral and mature tones, I see it having a wide audience that goes beyond teenagers. I wouldn't say it's for kids, but I can see many adults enjoying it. Lethe consists of a single volume. Highly recommended.
Sadie Mattox for Library Journal
In an attempt to save humanity, a dying Earth sends out shuttles with a human genome project on board. The ships are designed to land on different planets and birth humankind again. In Universe year 987, two factions of these projects are engaged in war. For those caught alive, the punishment is not death but a process called Lethe-the subject will forget all his memories, his personality, and his loyalties to live a new life. Mazda Hun is a soldier facing Lethe and pondering the mercy of this fate; he recalls his life in bits and pieces, focusing on a mysterious woman who may or may not have betrayed him. Though memories are not always pleasant, Hun decides they are better than nothing and begs for death. The frailty and subjectivity of memory is exposed in lush watercolor, and the artwork alone is worth purchasing a copy-the watercolor adds a sense of madness and vibrancy: it is Hun's stream of consciousness poured out on the page. Libraries looking to add some good manhwa can satisfy their older teens and adults with this highly stylized sf story.