During a visit to
Tenebrae, Regis and Noctis—who is recuperating from a near-death experience—are
targeted for assassination by Niflheim. Tenebrae is subsequently attacked, and
in the invasion Queen Sylva is killed by Niflheim's General Glauca. Regis
attempts to flee with Lunafreya, but she decides to stay with her brother
Ravus; both become subjects under Niflheim's rule.
Twelve years later, the
Kingsglaive fight to protect Lucis's borders from attacks by Niflheim's Magitek
army and Daemons, unnatural monsters tamed for military use. During one such
operation, Nyx Ulric defies his orders to withdraw to rescue his friend
Libertus from a Daemon. Regis, whose magic powers the Wall and is growing
weaker due to advancing age, accepts Imperial Chancellor Ardyn Izunia's offer
of peace. This causes dissension among the Kingsglaive, who feel Regis is
abandoning their families. Two days before the treaty is to be signed,
Kingsglaive member Crowe is sent on a mission to escort Lunafreya to Lucis, but
is killed en route. Her death causes Libertus to leave the Kingsglaive and join
a group of Lucian rebels. At a party dedicated to the signing of the treaty,
attended by both Regis and Niflheim's emperor Iedolas Aldercapt, Lunafreya
meets with Nyx before being secretly abducted by Glauca. Nyx discovers this and
finds that Niflheim has stationed their army outside Insomnia.
Regis agrees to deploy
the Kingsglaive, although their commander Drautos has disappeared. While Nyx
succeeds in rescuing Lunafreya, many of the Kingsglaive turn on him; Nyx,
Lunafreya and rebel leader Luche Lazarus escape as the ship disintegrates. At the
treaty-signing ceremony, the Niflheim delegation springs a surprise attack and
kills the ruling council, while their army enters by destroying the Wall with
help from the rebels, who are subsequently massacred. Lunafreya and Nyx reach
the Citadel just as Regis is battling Glauca. During the fight, Glauca cuts the
Ring of the Lucii from Regis's hand. Ravus attempts to put on the Ring and
claim its power, but it rejects him and destroys his arm before he can remove
it. Nyx, Lunafreya and Regis retrieve the Ring and flee with Glauca in pursuit.
Regis forces the two to go on without him, dying in his ensuing battle with
Glauca. Aldercapt and Ardyn—having successfully stolen the Crystal—leave
Insomnia to be destroyed by Niflheim's Daemons.
Summoned to the city
plaza by a call from Drautos, Nyx and Lunafreya are cornered by Luche, who
reveals himself to be Crowe's killer. Luche almost kills Nyx before being
tricked by Lunafreya into putting on the Ring, resulting in his death. Drautos
then appears, but is attacked by Libertus, who reveals that Drautos is in fact
Glauca. Just as Glauca is about to kill them, Nyx puts on the Ring. He is
confronted by the spirits of the past kings of Lucis; initially rejected due to
being not of their bloodline, his resolve and the threat to the Crystal
persuade them to allow his use of their power at the cost of his life. After
fending off Glauca, Nyx returns the Ring to Lunafreya before entrusting her to
Libertus, telling them to flee. With the Ring's borrowed power he engages
Glauca in a titanic battle throughout Insomnia, animating the city's statues of
past rulers, known as the "Old Wall," to combat Niflheim's Daemons.
Their fight ends as dawn approaches, with Nyx mortally wounding Glauca; Nyx
dies shortly after as payment for using the Ring's power, wishing for Noctis to
rule well in the future. In the aftermath, Libertus escorts Lunafreya out of
the city, but she tells him to stay behind. Lunafreya then leaves with the Ring
to find Noctis.
