Undetectable Monsters! The Androids Appear! (Kehai o Motana Futari - Gumi! Jinzoningen, Arawaru; lit. "The Pair Who Don't Leave a Trace! The Artificial Humans Appear!") is the fifty-ninth episode of Dragon Ball Z Kai. It aired on May 30, 2010 in Japan and on March 8, 2011 in America.
Goku, Gohan and Piccolo are flying to Amenbo Island for their expected encounter with the Red Ribbon Androids. Goku warns Gohan not to go too fast and waste energy on the journey. He tells Piccolo that he won't know what kind of chances they have until they actually see the Androids in person. Piccolo is confident, but has an ominous feeling. Goku warns him not to get too involved, in case they need the Dragon Balls. The three catch up with Krillin, who is worried about how he'll be able to contribute to the Super Saiyan's battle. Gohan catches sight of Amenbo island, and they observe the large city of Sasebo. Gohan says they need to lure the Androids away from the island as soon as possible once they are found, to minimize collateral damage. Krillin senses Yamcha on the island's central mountain, and they go over there to meet.
Sure enough, waiting for them are Yamcha, Tien Shinhan and Bulma. Krillin is surprised that Bulma has a baby. Goku thinks her presence is not a good idea; she insists she just wants a quick look at the Androids, and will leave afterward. Krillin asks about the baby, and Gohan assumes it's Yamcha's. He indignantly says it is not; they broke up a long time before. Goku identifies the baby as Trunks, and his father as Vegeta. Bulma is dumbfounded as to how Goku could know that, since she wanted that information to be a surprise to the others. Piccolo asks where Vegeta is. Not even Bulma knows, since they don't live together, but she says he was training intensely for this day. Goku is certain he will come. Tien tells Goku that Chiaotzu will not join the fight. The time is 9:30. The attack is supposedly 30 minutes away. Goku gives Bulma one more warning to leave while she still can.
As time passes, Gohan and Krillin make funny faces to entertain Trunks. Piccolo detects an imminent arrival, which turns out to be Yajirobe in a skycar. He gives Goku a sack of Senzu Beans from Korin, then leaves, not wanting anything to do with the battle ahead. It's 10:17, and Tien reminds them the Androids have not made their presence known yet, not even with a detection of ki. As Yamcha begins to think it was a trick, Yajirobe's car explodes in the distance and crashes into the sea across the island from them. Piccolo sees two figures in the distance flying down into Sasebo, but cannot feel any ki from the figures. Gohan figures out that as Androids, they don't even have ki. The Z Fighters have to find them on foot.
Goku, Piccolo, Krillin, Tien and Yamcha head into Sasebo. The Z Fighters split up in search of the Androids. Goku wishes he had a photo of the Androids from Future Trunks. Krillin and Piccolo only serve to scare the locals, while Tien, Goku and Yamcha are more discrete. Gohan fishes Yajirobe, who is unhurt, out of the sea and brings him back to Bulma and Trunks, who are holding onto the senzu beans. Elsewhere in the city, two figures land and go on foot. They are the Androids. Some locals ask if they saw the skycar explode. Android 19 approaches one man, his eyes flashing, then headbutts him before punching a second man. A car honks at Android 20, as he's standing in the road. Android 20 approaches the car and pulls its engine out of the hood. He then approaches the driver, grabs his throat and strangles him, lifting him out of the car. A woman watching the attack screams, alerting Yamcha, who rushes to the scene.
Android 20 notices a high ki approaching, which Android 19 hypothesizes is Goku, as its power level far exceeds any data they have collected. Yamcha arrives, and sees the carnage, with three humans laying in the street in various conditions from unconscious to dead. He asks some onlookers in a building who did this. They say it was an odd-looking pair, and they just vanished all of a sudden. As Yamcha thinks of alerting the others, the Androids observe from above. Android 19 confirms it is not Goku, and a scan reveals a high probability it is Yamcha. Android 20 thinks he'll be a good source of energy anyway, and they land. Yamcha doesn't think of them as Androids yet, and asks if they know about the attacks in the area, before noticing the insignia of the Red Ribbon Army on both of them.
Right after he calls out to the other Z fighters, Android 20 grabs Yamcha's face and overpowers him, lifting him off the ground. A gas tanker swerves to avoid them, crashes into a gas station and explodes, which alerts the others. Yamcha can feel his energy being drained. Then, Android 20 shoves his fist through Yamcha's chest. As Bulma, Gohan and Yajirobe see the apparent beginning of the fight, and locals try to flee, Yamcha loses blood, and eventually consciousness as well. Android 20 pulls his hand out of Yamcha's chest, making him bleed rapidly. The other Z Fighters detect the rapidly falling ki, and rush to the scene.
As Goku, Tien, Krillin and Piccolo arrive, Android 20 throws Yamcha's dying body at their feet. Goku tells Krillin to get Yamcha away and give him a senzu bean before it's too late. Android 20 is surprised that they knew they were Androids, and knew where they would appear. Piccolo says they will have to force the reason why out of them in battle. Goku says they need to be somewhere uninhabited. Android 20 agrees, but says there is no need to relocate. He proceeds to use Eye Lasers to annihilate half of Sasebo, before Goku stops him, punching his hat off to reveal his brain in a glass dome. The Z Fighters look in horror at the devastation. The others, including the restored Yamcha, also watch.
Android 20 detects Goku is unsatisfied with his solution to finding an uninhabited place. Android 19 says the Z Fighters will be unable to defeat them no matter where they fight, but the Androids agree to relocate with Goku, allowing him to "choose where you would like to die". The others are surprised the Androids know their names. As the authorities arrive, the fighters and Androids depart. Yamcha, Krillin and Gohan decide what to do. Yamcha has to warn the others that the Androids can drain ki from living beings.