The story centres around the unhappy Hans Burgner, a miller's son born in the 16th century. After the death of his weak father and of a likewise miserable but beloved teacher, he becomes afraid of the unavoidable death of all living things. Driven by a monomania fed by persistent rumors of an Elixir of Immortality, he becomes an apprentice of a mysterious physician and alchemist. However, instead of listening to the Alchemist's compassionate counsel and warnings, Burgner is driven by feverish greed to murder him; in this way, he acquires Elixir while he is still spiritually unprepared, and is cursed thereby. This is the starting-point of a journey through the centuries: while Burgner can physically die, the Elixir enables him to retain the full memory of his previous lives as he repeatedly reincarnates into a variety of different circumstances. It also bestows upon him a profound spiritual sensitivity. Several times he attempts the Great Transmutation in order to deliver himself from his self-imposed curse. Hans Burgner is refined through his various incarnations. Against the backdrop of the last five centuries of European history, he undergoes dramatic personal development: beginning as a spiritually unawakened (and even infamous) character, he matures spiritually through the various challenges he is led to confront. He is first an initiate and Aspirant, eventually attaining the perfection of human personality which characterizes the Magus, or spiritual Adept.
The Red Lion contains examples of the following tropes:
- Blessed with Suck: The protagonist can remember his past lifetimes as a result of drinking the Red Lion - and cannot shake off the painful memories.
- Chastity Couple: Lepitre and Rosalie. It does not end well, as it is based on self-denial. He is tempted by the vamp Corinna, and Rosalie offers herself to him as a "lesser sin". He rejects her, and she murders him and commits suicide.
- Fate Worse than Death: Hans Burgner gets plunged into a living demon-filled hell and wishes vainly for death.
- Gold Digger: Louis de la Tourzel senior only marries Sophie Petion for her money, having been prepared to abandon her until her sudden inheritance.
- Justice Will Prevail: "I did not realize then that earthly law merely executes spiritual justice, even when it seems to punish the innocent. No innocent man is ever punished; he is always caught by his own actions."
- Karmic Nod: Cornelius feels only peace when he knows that his crime is coming back to him through the hands of Ernst.
- Rule of Seven: The determined moon priestess in the tale told by Cornelius' father makes an appeal to the moon for seven years before finally getting a response.
- Sweet and Sour Grapes: Hans' greedy desire for eternal life fades as he becomes more enlightened through his subsequent lifetimes, and then he essentially achieves what he originally wanted anyway.
- To Hell and Back: The protagonist's time spent in his self-imposed hell, and his quest to climb out of it, is what makes his enlightenment possible.
- Whole Episode Flashback: The Framing Device of Adam Cadmon's manuscript turns the main story into a flashback.