Colonel McQueen and the Wild Cards are in a firefight on planet. Their extraction point is 100 klicks away, and they will not be able to make it on foot in time, especially with no cover from enemy fire. But the Colonel spots an APC a short distance away, and he tells them all to prepare to be "spam in a can". They make a break for it, but Vansen is hit. Nathan carries her over to the APC, and they all get inside it. Also destroyed in the retreat is their radio, making them unable to request another rendezvous point.
Once inside they close the hatch and try to get the APC up and running, but it's been damaged. Someone knocks on the hatch, demanding to be let in, and they meet Sgt Louie Fox, the APC's driver. However, the good Sergeant takes offense at "Pearly", his vehicle, being referred to as an APC. She is a tank, and no one but him can get Pearly to run as she should. He quickly demonstrates his facility with his beloved tank, and they put some distance between them and the pursuing Chigs.
Once they are well under weigh Col McQueen orders Sgt Fox to take them to their Alternate Rendezvous Designation so that they can get Vansen the medical attention she needs. He and the Sgt bicker, but they come to an agreement on some ground rules, and head for the ARD. The Sgt avoids one booby trap left by the enemy, but falls into another trap created by an ally. They dismount and start making repairs. As they do so, Fox and McQueen discuss the fact that they are being followed by someone unknown, but seemingly not Chigs.
Out of nowhere pops up a Maj. MacKendrick of Great Britain's Coldstream Guards. He admits to being the one who created the trap that they fell into, and offers any assistance he can provide. He is, however, all alone, with a radio that is unable to transmit and extremely limited supplies. Still, he takes them to his shelter and shares his water and knowledge of the area and Chig movements. Maj. MacKendrick's entire battalion was killed eight months previously, and the Major remained in the area to study the enemy to discover anything useful he could use to help defeat the enemy, or so he tells the Colonel. McQueen is dubious about his story, and tells him that he will be accompanying them to the rendezvous point whether he wishes to or not. The Major is unhappy, but is unable to dissuade him. But the 58th is suspicious that this strange man might actually be working with the enemy.
Sgt Fox stays to fix Pearly, and succeeds in getting her out of the ditch intact. But a Chig transmission comes over MacKendrick's radio, and he warns them that the APC is about to be attacked by Chig planes. Sgt Fox mans the tank's guns and defends his beloved vehicle and is killed. Fortunately, the Chigs leave the APC relatively undamaged, and the 58th and their unwilling companion are able to continue to the ARD. First they bury the Sgt, and then Vanessa tries to drive his beloved "tank" as he would want her to be driven. Pearly responds favorably to her new driver, and they leave the area, but not before McQueen notices the mystery people following them are still out there.
As they move out, McQueen orders Wang, Hawkes and West to do some discrete recon for those following them. Separated from the others, Wang is ambushed by a pair of Silicates- an Elroy El and a Feliciti Oh. After Wang makes a stray remark about being tortured by another Elroy unit, this one realizes he has a hold over the marine, through Paul's confession to war crimes when held prisoner at the Kazbek Penal colony. Elroy tells Wang that Feliciti is dying, and he needs a power cell to prevent that from happening. The AI has somehow fallen in love with her, and he will spare Paul's life and will erase all memory of the confession if he brings him the cell. Paul knows that there's only one spare cell, but the shameful memory is too powerful, and he decides to cooperate.
He steals the cell to give it to the Silicate. But then the APC's cell dies, and when it's loss is discovered everyone blames Maj. MacKendrick, who vehemently protests his innocence. He's bound and placed under guard, while they set up a solar recharger for the APC's fuel cell, needing two hours of daylight to get enough juice to make it to the rendezvous point. Hawkes talk to MacKendrick, trying to understand why the Major would strand them, and he tells Hawkes about his experiences in the war- ample reasons NOT to betray them to the Chigs.
Wang sees his chance to take the cell to the Silicates, but something about his actions seems strange to West, who follows. Elroy speaks words of mourning over the fading Feliciti, but eagerly attaches the cell to her when Wang brings it. West runs up and fires, and the Silicates run off, but not before they drain the cell dry. Wang tries to come up with a story as to how he found them already with the cell, but West isn't buying it.
Back at Pearly, West frees MacKendrick, saying he's innocent, and tells Paul to tell them what he did. He tells them, and then tells them all why his shame was so great that he did such a thing to them. They all understand, including MacKendrick, who generously forgives Paul for his silence when he was accused. But now they still have to make it to the rendezvous, and with only a short time left to recharge their cell, they don't know if they will make it. Vanessa tries to start Pearly, who doesn't respond until she sweet talks the "tank" the way Louie did.
Once under weigh they hear a Chig tank not far away, and Wang figures out that they are being tracked by a piece of the Silicate Elroy El they brought to explain Wang's betrayal. Wang and MacKendrick bravely combine to destroy the enemy tank, but then Elroy pops up and says he's going to kill Wang for failing Feliciti, who is now dead. MacKendrick shoots the AI, and they continue on. Pearly almost runs out of juice, but they still make it to the rendezvous just in time. The 58th board the ISSCV, but in the rush Major MacKendrick manages to stay behind with Pearly, much to their amusement. They know that he is a man to be trusted, and might just find the secret to beating the Chigs given enough time to study them.