Main timeline
In the plot premise of the original series, Magical Girl Lyrical Nanoha (2004), 21 "Jewel Seeds", highly destructive artifacts from another dimension, are accidentally scattered across Earth. After Nanoha assists an injured extradimensional magician in collecting them, she is drawn into a magical battle against a female mage named Fate Testarossa, who came to Earth to collect Jewel Seeds for her mother Precia. Attracted by their activity, the interdimensional police TSAB ("Time-Space Administration Bureau") intervenes to secure and to seal the artifacts. In the end, Nanoha convinces Fate to rebel against Precia, who is defeated and apparently dies.
In Magical Girl Lyrical Nanoha A's (2005), Nanoha continues her magical training. Six months after the original series, she and Fate encounter the "Wolkenritter", four magic knights who steal others' magical abilities to save Hayate Yagami, a wheelchair-using Japanese girl. Since the Wolkenritter are skilled in Ancient Belkan combat magic far superior to theirs, Nanoha and Fate fail to stop them and the Book of Darkness, an ancient artifact bound to Hayate, is activated. A worldwide catastrophe is only prevented thanks to TSAB and most importantly, Hayate's intervention. In the following years, all primary characters leave Earth to pursue magical careers in the TSAB homeworld Midchilda.
Magical Girl Lyrical Nanoha StrikerS (2007) takes place ten years after A's and is set on Midchilda. Hayate, now a Lieutenant Colonel of TSAB, forms a special Riot Force 6 to counter the impending terrorist crisis organized by Dr. Scaglietti, a former colleague and accomplice of Precia Testarossa, and his combat cyborgs ("Numbers"). Nanoha, Fate, and the Wolkenritter join the unit, along with four young mages whom they personally train ("Forwards"). Despite their preparations, the unit fails to protect Vivio, a girl targeted by Scaglietti and adopted by Nanoha, and the crisis strikes in full force, stopped in the nick of time by Riot Force 6's heroic efforts. The unit is then dissolved, with its members returning to their original posts.
A Drama CD titled Magical Girl Lyrical Nanoha StrikerS Sound Stage X (2008) is set three years after the Jail Scaglietti Incident. It features the characters first introduced in StrikerS, mainly the Forwards and the Numbers, investigating a serial murder case on Midchilda. Their investigation eventually leads them to the Mariage [sic], semi-sentient humanoid weapons from the Ancient Belkan era, and their elusive creator, Dark King Ixpellia.
Vivio's story is continued in the manga Magical Girl Lyrical Nanoha ViVid (2009-2017), which is set four years after StrikerS. Vivio now attends a magical academy on Midchilda, where she meets Einhart Stratos, another descendant of the Ancient Belkan royalty. Together with their friends, the two of them participate in the Inter-Middle, a magical combat tournament for young mages. A spin-off anime series, ViVid Strike! (2016), stars a teen magical martial artist Fuka Reventon, who trains under Einhart for a rematch against her estranged childhood friend, Rinne Berlinetta.
Another manga, Magical Record Lyrical Nanoha Force (2009-2013, on hiatus), set six years after StrikerS, focuses on a new protagonist, Thoma Avenir. After Thoma rescues a mute girl named Lily Strosek on remote world, he unwittingly becomes a fugitive from TSAB. The ex-members of Riot Force 6 join forces once again to avert a new crisis caused by dangerous Ancient Belkan legacy, the Book of the Silver Cross, to which Lily is apparently connected, and the Hückebein family, an interdimensional terrorist cell with sights on Thoma.
Alternate timelines
The PlayStation Portable video game Magical Girl Lyrical Nanoha A's Portable: The Battle of Aces (2010) is set in an alternate timeline which diverges from the main series at the end of the second anime series. In it, Nanoha and Fate refuse to seal Reinforce, allowing the Book of Darkness to regenerate its defenses and use the heroes' own dark clones to attack them. In the sequel, The Gears of Destiny (2011), the heroines must battle time-traveling humanoid Gears for the future of their respective worlds, and even meet characters from the future (of the main timeline).
The first two theatric movies were largely faithful adaptations of the first two anime seasons, but starting with Magical Girl Lyrical Nanoha Reflection (2017), the movies' continuity sharply diverged from the main one by cross-introducing the Gears (who are human in this continuity) to the Earth after Reinforce had been sealed. Magical Girl Lyrical Nanoha Detonation (2018) concludes the story arc that started in Reflection.
Magical Girl Lyrical Nanoha Innocent (2012-2014) is a spin-off manga series set in a universe parallel to the main franchise, where the main characters are ordinary girls who battle each other in a magical card game called "Brave Duel". A follow-up sequel manga, Magical Girl Lyrical Nanoha Innocents (2014-2016), featuring younger Subaru and Teana was published after the first spin-off ended.
