The Tail Section

Lot’s of info on ‘?’ both official and by way of spoilery insinuations.

From ABCMEDIANET

"?" - Mr. Eko enlists Locke to help find a secret location he believes houses answers to the island’s mysteries. Meanwhile, Jack and the other survivors struggle to cope with the horrific situation in the hatch, on "Lost," WEDNESDAY, MAY 10 (9:00-10:01 p.m., ET), on the ABC Television Network.

Guest starring are Adetokumboh McCormack as Yemi, Peter Lavin as Caldwell, Oliver Muirhead as monsignor, Melissa Bickerton as Joyce, Felix Williamson as Dr. Ian McVay, Nick Jameson as Richard Malkin and Brooke Mikey Anderson as Charlotte Malkin.

Richard Malkin was the psychic in "Raised By Another", and Brooke Mikey Anderson is someone who delivers a message to Eko at the airport in this episode.  What is her connection to the psychic?  And what connects the psychic to Eko.  And Yemi played Eko’s brother who should be dead. There is a Doctor involved.

An unsubstantiated rumor is that this episode deals with healing.  Eko becomes aware of the healing properties of the island and, convinced he can save whoever was wounded in the hatch, enlists Locke to help him find the mysterious ?,  which he assumes in the center of the islands power.

Also, per the call sheet, Libby appears in Eko’s flashback.