Amélie is a loner who observes the world instead of interacting with it. She sits in her Paris apartment looking out the window or in the Montmartre cafe where she works, and watches the unhappiness around her, transforming it into something magical and mysterious in her imagination. But one night, chance helps her discover a small box filled with a child's treasures. When she returns it to its owner and it brings him happiness, the course of her life is changed. She decides she wants to be someone who secretly brings joy to people — and by fulfilling that mission, she herself finds love. This was the plot of the 2001 film "Amélie" and the new Broadway musical follows along. The movie was aggressively whimsical, which people either loved or hated. Interestingly, when the musical goes that route, it's charming as when a nun strides by wearing an alligator mask. When Amélie meets her love, she's instantly surrounded by a flutter of hearts that pop out of briefcases. The production team has captured a surprising quirkiness that's often wonderful. But when the musical attempts to explore real feelings — loneliness, isolation, fear — the glow dims. It's not terrible. It's just meh. Part of the trouble is that Philippa Soo, who plays Amélie, often feels chilly and remote. Amélie is trapped in her head, but instead of letting us in, Soo's sprite pushes us away. This is surprising, because Soo is a genuine Broadway talent, who has showcased a range of emotions in her previous work, most notably "Hamilton."  But the blurry ballads don't play to Soo's power pop vocal strength, and as her character becomes more and more fearful, the cuteness around her starts to feel tinged with mania. Instead of feeling like we're lucky to be part of her world, we pity her — and that pity takes the magic away.    Amélie Book by Craig Lucas, music by Daniel Messé, lyrics by Nathan Tysen and Daniel Messé; directed by Pam MacKinnon At the Walker Kerr Theatre; open run