"Ignore the Green Mist to the Left"

But in all seriousness, "Remember the Signs" is a lovely tagline.

I would shorten it up to "Remember" or "Always Remember."

The darkness of Underworld arises.

I love "Remember the signs" as a tagline, and I also like the idea of seeing "Many fall down, and few return to the sunlit lands" as a tagline as well—it does a good job of conveying that the quest the main characters are undertaking is a very perilous one.

I rather like Lewis' early attempts at titles all strung together.
Knights under Narnia, Gnomes under Narnia, News under Narnia
Or something similar.
"Remember the signs" has been mentioned several times, but I also like what else Aslan said: "Believe the signs" or "Pay no attention to appearances."

"I'm on Aslan's side even if there isn't any Aslan."

I feel like that might be a slightly deceptive tagline, given that Aslan will appear very early on in the film and it's not like he's AWOL, but it's such a great line in the book and it could definitely grab people's attention.

Wow....I was the one who suggested "Follow the Signs" in the original thread, and I'm flattered that people like it But I think I even like "Remember the Signs" better! Great suggestion! It sounds all mystical and magical and Narnian

"I'm on Aslan's side even if there isn't any Aslan."

Oooooooooh... I can see a trailer or TV spot pushing that angle... that would be neat. It'd have clips of Caspian setting off to look for Aslan, the Witch's speech, perhaps the children despairing before reaching Harfang.

My favorite is still "Remember the Signs" because that really does sum up the arc of the movie.

I think a mix would be nice. What if in the end of a ACTION filled sensational trailer, the screen turns black and we hear Aslan's voice narrating: "Remember the signs and believe. Nothing else matters . . . " Then the traditional Narnia Title music comes on and . . . THE CHRONICLES OF NARNIA: THE SILVER CHAIR

Aslan Fan, really, really, really like your suggestion!!!
I believe if The Silver Chair is done correctly, it could be a SUPER movie

Actually I'd prefer the tag line to be: "Remember the signs and believe the signs. Nothing else matters". Small difference, I know. But I think it is more relevant to missions, journeys and belief systems alike.

Thought of another possibility for a tagline, although I'm not sure if it's too long: Could you believe me if I said that I'd been out of this world? Paraphrasing what Eustace says to Jill behind the gym. It's definitely an attention-grabbing line, but it's a bit long, yes.

^ Yeah, that's probably too long for the tagline. I could see it being effective in a trailer though.

Rose-Tree Dryad, I love that line.But, I would like to see that line in the movie and in the trailer. To me, ''Trust the Lion'' would be a good tag line.

I have an idea, what about a series of dramatic verbs describing the things Jill and Eustace go through?

For example:
Accept the Mission, Survive the Journey, and Triumph Over the Darkness

Accept the mission, survive the journey, and discover a dark plot to undermine Narnia (pun intended)

This is my favorite
Accept the quest, survive the journey, and encounter a foe with plans that go far deeper than could be imagined

There are so many possible combinations! If anyone thinks of a better combination, please post it.