(Japanese: ニビジム・史上最大の危機！Nibi Gym - The Greatest Crisis Ever!) is the second spin off of the Diamond & Pearl series of the Pokémon anime. It first aired in Japan on February 3, 2011 in a one-hour special with SS024.
After his journey with Ash and Dawn, Brock returns home to take care of his siblings as well as studying towards gaining entry to a training school for Pokémon Doctors. Two of Brock's younger siblings come into his room and let him know that it is time for lunch. Brock gathers his siblings to the kitchen so that he can make them lunch, since their parents are away on yet another vacation. Meanwhile, at the Pewter Gym, Forrest calls out his Steelix to battle a challenger. The challenger refuses to battle and requests to battle with Brock or Flint only. After gathering the rest of his siblings, Brock finishes the meal and they get ready to eat. One of Brock's younger brothers runs into the kitchen and tells him to go to the Gym right away and that there is a challenger refusing to battle anyone but Brock or Flint. Brock and his siblings head towards the Gym and Forrest tells Brock about the situation. Brock recognizes that the challenger is really Nurse Joy and falls in love with her. Croagunk stops Brock with his Poison Jab. The challenger reveals that she used to run the Saffron CityPokémon Center but is now a top-level agent of the Pokémon Inspection Agency. Forrest explains to his younger siblings that Gym Inspectors test Gym Leaders to ensure they will present a decent challenge to Trainers, and have the power the revoke the right to give out Badges or even shut down the Gym completely.
Brock explains to Nurse Joy that he gave the Gym Leader position over to Forrest. Nurse Joy tells him that she did not receive any notification of the Gym Leader change. Nurse Joy agrees to battle and assess Forrest's ability to be a Gym Leader. Nurse Joy brings out her Chansey and Brock brings out Sudowoodo. Chansey uses Minimize to avoid Sudowoodo's Hammer Arm. Chansey then uses Attract to infatuate Sudowoodo. Sudowoodo is unable to attack so Chansey hits him with a Double Slap and knocks him out with Egg Bomb when Sudowoodo tries to attack with Flail. Nurse Joy tells them that she will not be giving a good review based on the battle and that they should expect bad news. Nurse Joy tells them she will be remaining in the Pokémon Center until the next day and to come see her if they have any questions or comments. Brock and his siblings start to become very worried that the Gym may be closed down.
Flint and Lola arrive back from vacation with gifts for their children. A Dugtrio ornament for Brock, Vileplume poster, two Exeggutor ornaments in a bag, and a Smoochum ornament for the younger children. Lola and Flint start talking about their trip and how great it was, when Brock interrupts them to yell at Flint about the notification Brock was asked to turn in. Flint explains that he found a rock that he really liked, put the notification envelope on the ground and left it there. Brock is furious when he hears this. While they are arguing, Sudowoodo and Marill are playing around with Brock's baby siblings. Flint and Lola tell Brock that the Gym closing down would be a good thing and that they would be able to change the Gym into a restaurant. However, Brock hates the idea.
Brock heads to the Pokémon Center to speak to the Inspector Joy in her office. Brock asks her to give the Gym another chance and to test Forrest as a Gym Leader for the inspection. Inspector Nurse Joy says that she has to think it over. Just then Pewter City's Nurse Joy comes into the office and says she has a problem and Brock tells her exactly how to solve it. Brock explains to Inspector Nurse Joy that he is studying to become a Pokémon doctor which is why he wanted to hand the Gym over to Forrest. Nurse Joy decides that she will test Forrest with a battle and Brock goes home to tell everyone. Everyone is asleep in their beds but Brock notices that Forrest is not and goes to the Gym to speak about the battle. Brock gives Forrest some encouraging words while their mom and dad look on and say that they are very proud of them.
The next day, Nurse Joy and Forrest prepare to battle, while Lola and Flint give their younger children Hawaiian outfits to wear for cheering on Forrest. Forrest brings out Rhyperior and Nurse Joy brings out the Legendary PokémonLatias. Everyone is worried that Latias will be too much for Forrest to be able to win. Rhyperior starts off with Megahorn on Latias who uses Dragon Pulse to counterattack. Rhyperior dodges with Dig. Latias uses Recover before Rhyperior comes back to the surface. Latias strikes a strong hit on Rhyperior with Ice Beam. Latias tries the attack again but Rhyperior dodges and counterattacks with Megahorn, which connects. Rhyperior uses Dig again and uses Megahorn from behind to land a hit on Latias. Latias uses Recover once more, followed by Dragon Pulse and Steel Wing. Latias then finishes Rhyperior off with one last Ice Beam. Forrest goes down to his hands and knees thinking to himself that his loss will cause the Gym to be closed down.
Forrest and Brock go to attend Rhyperior, and Brock tells his Pokémon to get some Sitrus Berries so that they can heal Rhyperior. Nurse Joy informs Forrest that she was impressed with the battle and that she will give a much better review than before so they can expect the Gym to keep running. She also tells Brock that after witnessing his skills she is certain he will be an excellent Pokémon Doctor. After Rhyperior is healed, Nurse Joy prepares to leave. Brock expresses his love to her, and Croagunk uses Poison Jab to stop him. Everyone says their good-byes and Nurse Joy heads off.