Ororo, in a security uniform, is patrolling the perimeter of a building. Shadowcat phases upward from the ground and knocks her out with gas from a spray can. She talks into her microphone and says that the north perimeter is secure. Spyke is watching Logan from above. He jumps down and also knocks him out with gas. He speaks into his microphone and says that the south perimeter is secure. Cyclops says to make it a clean rescue.

During a training exercise, Cyclops and Nightcrawler teleport inside a skylight. As soon as their in, Jean catches them and telekinetically lowers them near the ground where the alarm system's motion detectors are seen along with a cloaked figure chained to a post. Cyclops
calls Storm's name, but realizes that she's out. He shoots optic blasts at the chains and hits them on the third try, while Jean complains that they're heavy. A dark figure sneaks up on Jean and grabs her, causing her to drop
Cyclops and Nightcrawler. The alarm sounds and Cyclops runs towards the cloaked figure and tells Nightcrawler they need to grab Storm and teleport out. But it turns out that the figure isn't Storm -- it's Rogue. Rogue reaches out and touches Cyclops' face, and begins to absorb his power.

Cyclops struggles and Rogue absorbs his power, then shoots Nightcrawler. Cyclops calls for the simulation to stop, and Rogue, now a lifeless robot,falls to the ground. Xavier enters with the others and tells Cyclops that he's never to stop a session unless he's hurt. Cyclops asks why Rogue was in the simulation, because she wasn't in the briefing. The Professor tells him it was to surprise them, and that they should be ready for it on every exercise. Cyclops looks down at the Rogue robot angrily, and Jean looks at him worriedly.

At school, students are loading a school bus for the field trip. Rodetski, the teacher, rattles off a list of spelunking gear the students should double-check for their trip to the Tapo Caves.

Scott and Jean are talking on the way to the bus. Jean asks him why he's so upset, and Scott says it's not because he messed up, but because if they think of Rogue as the enemy, she'll never want to join them. Jean tells him it was just a simulation and that he shouldn't stop trying with Rogue.

Principal Darkholme has heard the whole conversation. Rogue is working out in the empty gym. She sees Jean and Scott outside and closes the window's blinds, but continues to watch them through the blinds. Darkholme comes up behind her and says that he's never going to be her friend. She reminds Rogue that he and his friends attacked her, and tells her that they used her as their target in their battle simulation. Rogue asks why they would do that but Darkholme just responds by saying that she needs to be reminded of who her friends really are. She drops a pack in front of Rogue and tells her to "Enjoy the field trip".

Rodetski tells Jean that her spot has been filled because, of too many unexcused absences. Scott says they were approved and Jean says that Rodetski can call Xavier, but he tells her there's not enough time and that he's sorry. Rogue flashes Scott a look as she boards the bus, and Scott
frowns.

Professor X is at his desk. It's windy outside and he moves to close the window. He gets pushed back suddenly by a force and hits a dresser. He asks Magneto why he has come. Magneto says he compliments him on his "young charges". Xavier, says Magneto, doesn't trust them? Xavier protests and says he trusts them with his life, "but," Magneto adds, "not with the truth!" With that Magneto pulls Xavier's wheelchair suddenly to the window, where his wheelchair crashes into it, breaking the glass. Magneto is nowhere to be seen.

The students are on the bus. Rodetski sees that it's starting to snow, and says too much snow means they'll have to turn around. Scott and Rogue are sitting in the back separate and alone.

Later, the bus suddenly slips and skids on an icy cliff road. Rodetski tries to get the bus under control, and Scott, thinking fast, pulls down the window next to him and burns a ditch into the ground near the edge of the cliff. The bus teeters but its wheels lock into the ditch, saving it from toppling over the cliff. Scott quickly closes the window and sits back down, but he looks back at Rogue, the only one on the bus who knows that he saved all of their lives. The two exchange smiles. Rodetski wants to turn around, but Rogue suggests that they take their snowmobiles to the cave and wait out the weather there.

On their snowmobiles Rogue challenges Scott to a race. Although Rogue's passenger protests, they begin racing dangerously. At one point, Rogue pushes her mobile against Scott's, so that he and his friend Paul almost topple over a cliff. Paul says it seemed like she didn't care what happened to them, and Scott wonders why. At the cave Scott asks Rogue how she learned to ride a snowmobile, and Rogue responds that she's "just full of surprises".

Back at the mansion Logan and Xavier are discussing whether or not they should tell the students about Darkholme's true identity. Logan thinks the students are mature enough, but Xavier has doubts. Ororo enters with Jean to tell Xavier about the blizzard in the mountains. Jean tells them that
Darkholme gave her spot on the trip to Rogue.

In the cave Rodetski starts a lecture on geology. Scott notices Rogue slipping away and follows her. He is amazed to see a waterfall in the cave, and he walks towards it. Entranced by the waterfall he finds himself at the edge of a seemingly bottomless chasm and barely catches his balance. Scott looks for Rogue. Rogue confronts him and asks him what he wants from her. Scott says nothing, except her friendship. She tells him that she knows about the battle simulation and Scott tells her that the X-Men have never attacked her and that they want her to join them, but she starts to leave angrily. She passes Paul and says Scott wouldn't use him as a target. Paul moves forward and changes to Darkholme and then Mystique. She taunts Scott,
because Xavier didn't tell them about her true identity, and then she suddenly shoves him into the chasm.

Rogue rushes to the edge of the chasm, and angrily asks Mystique why she did that. Mystique says that she's "only trying to protect her". Rogue, fed up with lies, takes off her glove and grabs Mystique to find out the truth. In her mind she sees that Mystique had impersonated the X-Men in order to get her to join the Brotherhood. Mystique, energy drained, faints and Rogue, realizing she's been mistaken the whole time, looks back down the chasm and sees Scott hanging onto a ledge by his fingertips. Scott looks up and sees Mystique jumping towards him, but it turns out to really be Rogue, who helps him onto the ledge. Scott thanks her, but just then the real Mystique pushes a boulder down on top of them. Rogue and Scott jump into the rushing river
below them. Scott gets them onto a ledge, which crumbles under their weight, causing them to land roughly onto a bridge-like rock exposed to the blizzard.

Scott thanks Rogue for saving his life. Rogue says Mystique's mind is "a tortured mess", but that she saw enough to know that he wasn't her enemy. She tells him she thought Mystique cared about her. Scott tells her that she
probably does, and that adults are hard to understand "because they never seem to trust us". Rogue becomes worried when Scott fades, while Mystique watches them from above.

Meanwhile Storm is trying to speed the Blackbird through the blizzard, although it is slow going. Mystique shifts into a wolf and menaces Rogue and Scott. Rogue tries to pull Scott away although the bridge seems weak, and Xavier tries to contact Scott telepathically. Scott tells Rogue that the X-Men are on their way, but they can't find them. Rogue gets an idea. She removes Scott's glasses and tells him to open his eyes. Wolverine immediately sees the burst of red light from Scott's optic beam. Rogue replaces Scott's glasses, then touches him and absorbs his power. She blasts Mystique off the bridge, but Mystique shifts into an eagle, as she falls. Wolverine arrives and tells her to give up, and he looks at Rogue shrewdly before grabbing the two of them and hauling them into the Blackbird just as the bridge collapses.

In the plane Wolverine asks Rogue where her allegiance is. Rogue asks if she's going to get thrown out of the plane if she doesn't say them. Wolverine says that's "not our style", but that they've either earned her trust by now or not. Rogue looks at Storm caring for Scott, and says she
wants to join. Wolverine welcomes her to the X-Men.

At the mansion the students are meeting with Xavier. Jean says they should have known, and Kitty and Evan agree. Xavier asks Rogue what she thinks, and Rogue hesitates. Kitty says she's part of the family now, and Evan
encourages her. Rogue says that she believes honesty is important between people you care about. Xavier apologizes for keeping Mystique's identity a secret, but says that there are still some secrets they're not ready to learn and in the future he'll try better to know the difference.