"Last Refuge," tonight's installment of "DC's Legends of Tomorrow," gets by on a simple yet dependable premise: the Legends have to rescue their younger selves before the Time Masters' assassin, The Pilgrim, kills them all. Them dying in the past would mean them dying in the present.

Given the large size of Rip Hunter's team, that alone would be enough to fill an entire episode, but like any storytellers worth their salt, writers Chris Fedak and Matthew Maala attempt to add some dramatic weight to many of the heroes' subplots. Sometimes, they're successful, like with Heat Wave. Seeing him help his teenage self understand his pyromania and intense feelings of guilt over the deaths of his parents (his fire addiction got out of control and he burned the house down) hits hard for a simple reason: We know Heat Wave. We're familiar with his inner battle of heroism and villainy as an adult, so we're able to project it onto another version of himself from the past.

But for the most part, these emotional detours flounder, as they're centered on characters we've never met before. If the show had more time to explore Jax's relationship with his military father, who he knows will be K.I.A. shortly after leaving the hospital where his son is born, maybe it could transcend the realm of truncated melodrama. But because the episode tries to touch on a past/present/future conflict for nearly every member of the main cast (White Canary bonding with her dad, The Atom having his one-time fiancee on the ship, etc.), the entire arc feels summarized and under-developed. There's just not enough time to get to it all in a narratively satisfying way.

"Last Refuge" does get a second wind in its final stretch, however, by honing in almost exclusively on Rip and his mother. A sci-fi take on Wendy Darling, her house in the English countryside has been a longtime refuge for orphans (including Rip) whom she raises to become Time Masters. Since it's off the historical grid, it becomes the perfect place to bring all of the "Muppet Babies" versions of the Legends. And because the episode has mostly cooled down story-wise by that point, there's enough time to see how Rip and his mom act around each other. There's enough time to learn more about their relationship.

Their dynamic holds a tenderness (she bakes him mince pies), but also a cold pragmatism. As much as it pains her, she has no problem with offering up Rip's younger self to The Pilgrim as a means to end her pursuit of everyone else. Of course, this is all part of the adult Rip's bigger plan; he knows there's no way that Rip Hunter -- even Rip Hunter as a little boy -- will let The Pilgrim take him so easily. The kid promptly stabs the assassin in the leg, allowing the Legends to incinerate her.

But pint-sized badass or not, it still takes a lot of courage for Mama Hunter to put her adopted son in such danger, and because we've gotten to spend some real time between the two characters, the sequence has legitimate tension. "Last Refuge" would have done better to stick to the Pilgrim thread and save the rest of the mushy stuff (save for Rip, his mother, and maybe Heat Wave) for later. Something tells me these characters will have plenty of more opportunities to revisit their past.