Moonlighting As a Hero is the first quest that runs inside the Hercules Realm in Disney Dreamlight Valley, and it kicks off the entire process of recruiting Hercules and Phil into your village. It begins on its own the moment you step through the Realm door, dropping you into unfamiliar ground where most paths are still sealed off.

Unlock the Hercules Realm first
Moonlighting As a Hero cannot start until you open the Hercules Realm. The door sits on the top floor of the Dream Castle and is marked with a cloud and lightning bolt icon, which makes it simple to pick out once you know the symbol.
The entry cost scales with how many other Realm doors you have already unlocked. If every other area is open, the price tops out at 14,000 Dreamlight, the highest you will ever pay to get inside. Once you walk through, the quest triggers automatically, and a cutscene shows Phil running past you.
Find and talk to Phil
Step 1: From the spot where you arrive, head straight ahead into the Realm. Keep going until you near the waterfall.
Step 2: Just before you reach the waterfall, turn right and follow the path downward. Phil is waiting at the end of it.
Step 3: Speak with Phil to start the real work. He explains that most of the Realm is blocked by dark thorns and strange fog leading toward the dark woods, so you will need to find a way forward before anyone can reach Hercules.

Gather the Moon Headband and Artemis's offerings
To clear the path, Phil sends you after a Moon Headband along with a set of nature offerings meant for Artemis. Placing these offerings is what lifts the barrier holding you back, so the route past the thorns and fog stays closed until you complete this errand.
Clear Phil's obstacle course
After the offerings are taken care of, Phil tests you with a tricky obstacle course. You have to prove your worth by getting through it before he lets you continue. Treat it as a movement and timing challenge rather than a fetch task.
Once the course is finished, the way forward opens and you can finally set off to track down Hercules himself, which leads directly into the next quest in the chain.

How to know the quest is done
Moonlighting As a Hero wraps up when you head out to find Hercules after passing Phil's course. At that point, the quest log advances to Speedrun Crash Course, the second mission of the Realm, where you start gathering materials to win over Hermes. If the next quest has appeared in your journal, Moonlighting As a Hero is complete.
From there, the road to recruiting both characters continues through Thunderstruck and A Real Godly Mess, followed by building Hercules' house for 10,000 Star Coins. Finishing this opening quest cleanly keeps that whole sequence moving without backtracking.