There and Back Again and Displacer Kitten on the battlefield.
There and Back Again has exactly two lore counters on it.
The mana requirement can be reduced by ({1} magic symbol) if you have a Mountain in your library and additionally by the greatest amount of mana a nonland permanent you control can produce when blinked.
At the beginning of your precombat main phase, when a lore counter is put on There and Back Again, its third chapter ability triggers.
Holding priority, cast Clockspinning with buyback by paying ({3} magic symbol) ({U} magic symbol) , targeting Displacer Kitten.
Displacer Kitten triggers, blinking There and Back Again, which enters the battlefield with a lore counter on it.
There and Back Again's first chapter ability triggers, causing the Ring to tempt you.
Resolve Clockspinning from step 3, returning it to your hand.
Resolve the There and Back Again chapter three trigger from step 1, creating a 6/6 legendary Smaug creature token.
Cast Clockspinning by paying ({3} magic symbol) ({U} magic symbol) , targeting There and Back Again.
Displacer Kitten triggers, allowing you to blink a nonland permanent you control if desired.
Resolve Clockspinning, putting a lore counter on There and Back Again and returning Clockspinning to your hand.
When the lore counter is placed, There and Back Again's second chapter ability triggers, allowing you to search your library for a Mountain and put it onto the battlefield.
Repeat steps 7 through 9 one additional time.
There and Back Again's third chapter ability triggers.
Holding priority, repeat steps 2 through 5 one additional time.
Put one of the Smaug tokens into your graveyard due to the legend rule.
When the Smaug token dies, it triggers, creating fourteen Treasure tokens.