Cast Invasion of Arcavios by paying ({3} magic symbol) ({U} magic symbol) ({U} magic symbol) .
Hullbreaker Horror triggers, returning up to one nonland permanent to its owner's hand.
When Invasion of Arcavios enters the battlefield, it triggers, returning Nexus of Fate from your graveyard to your hand, or searching your library for Nexus of Fate and putting it into your hand, if needed.
Cast Nexus of Fate by paying ({5} magic symbol) ({U} magic symbol) ({U} magic symbol) .
Hullbreaker Horror triggers, returning Invasion of Arcavios to your hand from the battlefield.
Resolve Nexus of Fate, causing you to take an extra turn after this one and shuffle it into your library.