(Note: Casting Infinite Reflection before Living Plane is recommended.
This combo has a chance of failure depending on the density of lands and creatures in your deck).
({5} magic symbol) ({G} magic symbol) , plus enough mana to cast the creature with flash available.
Steps
Cast Green Sun's Twilight with X equal to 5 or more by paying at least ({5} magic symbol) ({G} magic symbol) .
In response, cast a creature spell with flash by paying its mana cost.
The creature enters the battlefield as a copy of Dualcaster Mage, triggering its ETB effect, copying Green Sun's Twilight.
Resolve that copy, revealing at least the top six cards of your library and putting a creature and/or land card from among them onto the battlefield, then putting the rest on the bottom.
Each creature or land chosen this way enters the battlefield as a copy of Dualcaster Mage.