There and Back Again has exactly two lore counters on it.
An opponent cannot block and kill
Esika's Chariot.
Steps
At the beginning of your precombat main phase,
There and Back Again triggers, putting a lore counter on it.
There and Back Again's third chapter ability triggers, creating a legendary 6/6 Smaug creature token and causing you to sacrifice
There and Back Again.
Activate
Esika's Chariot's crew ability by tapping the Smaug token, causing
Esika's Chariot to become an artifact creature until end of turn.
Declare
Esika's Chariot as an attacker.
Esika's Chariot's second ability triggers, creating a copy of the Smaug token.
Put either Smaug token into your graveyard due to the legend rule.
When the Smaug token dies, it triggers, creating fourteen Treasure tokens.
Move to your postcombat main phase.
Activate five Treasures by tapping and sacrificing them, adding ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Activate
Aggravated Assault by paying ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) , causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat from step 4.
Notes
Once you have infinite mana, you may copy any other token(s) you control instead.