To build this deck, include nine of your favorite cards from the sideboard according to what the rest of the table is playing and shuffle them up!
This is a high-theme Timely Aid/Secrecy deck. Frodo and Sam are going on an adventure alone in the wilderness, and depending on whom they can find, they'll be able to make their way to success. I usually field this as a questing deck for my part in the table, but due to how flexible the unique allies can be, it can easily become a more balanced deck, and it even works solo!
The key, of course, is Timely Aid. You want to start with 2+ secrecy cards in your opening hand, preferably Resourceful and Timely Aid as those will immediately replace your missing third hero. Resourceful gets attached according to the needs of your hand, but the first one generally goes on Frodo and the second on Sam.
Bill and the Scouts are fantastic for telling an early Tale, and Northern Tracker/Knight of the White Tower give you more non-unique Tale/Aid targets that your heroes can actually play later on. Galadhrim's is a great way to either get back into secrecy, make up for a big Frodo-inspired threat hit, or drop someone else's threat if you're doing well. Don't be afraid to use Frodo's damage mitigation aggressively, despite being in Secrecy; once you've played about 3-4 Resourceful/Timely Aids you've done most of the work of the deck anyway, and a late-game Vanish can make them all cheap for a big turn.
Note: If available, I'm partial to exchanging Galadriel's Handmaiden for Arwen Undómiel and Vanish From Sight for Elrond's Counsel, which lets me do far more than just fake-Secrecy on the turns when I want to dump a bunch of cards into play for cheap. However, I've built it with this lineup to make it more multiplayer-friendly.