!! Short Summary
A special tie in arc meant to lead in to the movie ''Anime/OnePieceFilmZ''. The arc begins with the Straw Hats coming out of the ocean after leaving Fishman Island and being beset by the fierce and odd weater of the New World. After this, they soon meet a tiny woman who invades the Sunny named Lily. Turns out she's a giant who ate a fruit that allows her to turn into a miniature version of herself. After a brief scuffle, she befriends the crew and tells them of her dilemma involving her father Panz Fry, who's been captured by the Marines and is about to be sent to Impel Down. The crew agree to help her, but they aren't the only ones after him.

!! Main Summary

The arc begins with a few of ships gathering. A woman, Ain, proclaims the pirate age will soon be coming to an end. However she is told that one of their members, Shuzo, hasn't come back yet. They call him and find out that he has taken a detour so he can intercept a Marine transport and kill a pirate known as Panz Fry. Ain doesn't agree with such a plan but lets him do as he wishes, with a warning that he knows what the price of failure means.

Meanwhile, the Straw Hats land back in the ocean, but suddenly find themselves surrounded by a whole fleet of Marine ships. They prepare to attack but when Luffy hits one, his attack goes right through it. Nami realizes its a mirage and the ships promptly disappear. The crew is then beset by a whole number of strange weather anomalies like large raindrops that quickly turn to hail which threaten to crush or capsize the ship, which soon turn into a whole avalanche of snow, then the sea splitting and threatening to drop them into a whirlpool. They manage to escape and avoid damage (save for an errant lighting bolt).

They soon reach stable waters and take a break. Sanji goes to fix the crew something to eat, but as he prepares the food, he's unaware of something lurking in the kitchen. He finishes and calls the crew in which Luffy, Usopp and Chopper rush to grab some grub only to find an empty plate. Naturally the group is confused to where the food has gone, especially when some food Sanji just recently prepared goes missing in a matter of seconds. Something small hops out from one of the pots and onto the deck which Luffy chases after with a net. The small food thief being a viking helmeted female who avoids his swats. Franky tries to stop her but she surprisingly manages to toss him aside. Eventually the crew manage to surround her, but before they can do anything she suddenly changes size and grows into a giant (whose weight the Sunny can oddly support). Though she apologizes, she declares she's taking their ship which Luffy challenges her to. She attacks with a fork only for Luffy to grab it, lift her into the air and toss her out into the ocean. Since her powers are, of course, Devil Fruit related, she can't swim. Sanji dives in to save her where she shrinks back to small size.

After she comes to, she get to know the crew, introducing herself as Lily Enstomach or as she known "Lily the Glutton". She reveals she's actually a giant who ate the Mini Mini Fruit ''(Mini Mini no Mi)'' and can change her size at will, though prefers her small form as its better for sabotage coupled with her strenght which she keeps in her small form. She goes on to explain that she's after her father who was captured by marines and is being taken to Impel Down. Her father, who of course is also a giant, is a notorious pirate chef known for stealing from Marine cargo ships if only to use for his food so he can help the starving. He's also known for his "volcanic cooking" where he uses volcanoes to make savory dishes. Naturally Luffy likes the idea of getting a taste of such food and the Straw Hats and he agree to help her save him.

They don't have to wait long before they see a fleet of Marine ships sailing toward them with a giant tied to a raft in the middle of them. All of this overseen by Momonga who has since become a Vice-Admiral. Nami takes over operations and lays out the plan: the crew will each take a part of the solider dock system and spread out. Nami will oversee everything from her wave runner, Luffy, Robin, Chopper and Brook will be in paddle boat on stand by while Zoro, Usopp, Sanji, Franky and Lily will sneak in via the submarine, keep the marines distracted and free Panz Fry. Once that's done they'll hook Panz Fry's raft to the Sunny, regroup back to the Sunny and use a Coup De Burst to get clear. However as they go to set the plan in motion, it's revealed Luffy snuck aboard with those in the sub as he found his part in the plan boring. Much to Nami's irritation.

Regardless the plan seems to go off without a hitch, they manage to free Panz Fry and keep the Marines at bay. However just when it look like they'll succeed, the area is bombarded by cannon shells. Some of which which hit Panz Fry. Submarines, lead by Shuzo, suddenly surface and continue their attack. He eventually joins the fray himself by spinning toward the group like a cannonball. Luffy tries to deflect him with his balloon form but is knocked into the water. Shuzo lands on Panz Fry's raft where he recognizes Momonga as he used to be in the Marines. Though when he states his intention of killing Panz Fry, Momonga refuses to let him, not that Shuzo had any intention of letting the Marines live revealing he's part of the Neo Marines which are lead by Z much to Momonga's shock when he hears his name. Likewise Shuzo's crew chastise him for giving out crucial information.

Lily goes giant and tries to attack Shuzo, who dodges and nearly retaliates if not for Sanji saving her. He then orders his fleet to fire on Panz Fry, but just as the shells are about to hit. Momonga saves him, admitting while he doesn't want to help pirates he won't let Shuzo do as he pleases. Luffy is finally fished out of the water by Zoro and rejoins the fight, leading to a tense standoff between the parties.

It soon becomes a three way battle between Momonga's forces, Shuzo's forces and the Straw Hats with Luffy fighting Shuzo and Zoro clashing against Momonga. Sanji keeps the Neo Marines at bay with some help from Robin. Nami notices anomalies in the water and realizes the ocean will sprout up geysers called the "Thrust Up Stream", smaller versions of the Knock Up Stream back in the ''[[Recap/OnePieceJayaArc Jaya Arc]]'' which can send ships flying. She has the Straw Hats regroup back to the Sunny, but when ready to do a Coup De Burst, Franky reveals the raft is much heavier then thought so they can't blast off. Nami quickly devises to use one of geysers for added propulsion. She times the ship to blast off just as one erupts under Panz Fry's raft and they take off with Panz Fry, Lily, Sanji, Luffy and Zoro just barely hanging on. Seeing this, Shuzo quickly throws a knife with a Vivre Card Card onto the escape log.

In the aftermath, Momonga's fleet is destroyed by the geysers and his remaining flotsam smashed by Shuzo who quickly sets after the Straw Hats. At a rock structure, the group relax with Chopper checking over Panz Fry's injuries and patching him up. Luffy ask for some of his cooking but everyone is mostly against this as Panz Fry is still wounded. However he agrees to cook for the bunch as thanks for saving him much to Luffy's joy. However unknown to the crew, Shuzo has located them. Though told they're out of cannon shells, Shuzo's men volunteer to kamikaze themselves toward the crew. Shuzo accepts this and prepares to attack.

Shuzo's forces launch at the crew, a few dying needlessly while others are knocked aside by Panz Fry and the Straw Hats. Eventually Shuzo comes out to personally deal with the group. Luffy goes to take him on, but both his Gear 2nd and his Haki attacks are not strong enough to beat him and he's defeated by a combination of a Haki infused cannon shell fired from Shuzo's alpaca, Alpacacino and a ten finger shigan attack. Seeing this Lily asks Usopp to fire her into Shuzo's mouth so she can expand and kill him from the inside. Usopp complies but just as she's about to reach him, Shuzo puts Luffy into her path and she flies does his mouth. All seems lost until Luffy recovers and then then suddenly expands into a giant form.

This turns out to be the work of Lily who expanded inside of him, since Luffy is rubber it changed his size without harming him. With the newfound advantage, Luffy goes Gear 2nd and quickly defeats Shuzo and Alpacacino. The threat neutralized, Luffy is all set to try Panz Fry's food only to find it was all ruined in the fight. But is cheered up when told they'll grab some food and find a volcano. Franky builds Panz Fry a raft from Shuzo submarie and the crew take off leaving Shuzo and his remaining troop tied up to one of the reefs. Momonga later finds him, having used the same trick Shuzo did to find Panz Fry, and has Shuzo shipped off to Impel Down.

Luffy and the crew manage to gather some new food material and get to try Panz Fry's cooking before parting ways with Lily and him. Some time later, news of Shuzo's imprisonment reaches Z. He takes the news in stride before being informed they've reach the first of their targets. With a vow that the Neo Marines will destroy all pirates, Z and Ain set out to fight leading into the events of ''One Piece Z''.

''Z's Ambition Arc'' has the following tropes:

* AdaptationExpansion: Somewhat, the arc begins from where the ''[[Recap/OnePieceFishmanIslandArc Fishman Island Arc]]'' leaves off, with the Straw Hats entering the New World from the ocean. Apparently the movie, Z, is meant to take place shortly after this and before they reach [[Recap/OnePiecePunkHazardArc Punk Hazard]].
* BigEater: Lily, just like Luffy. Which is part of the reason they got along so fast.
** Hell, Lily's RedBaron is "The Glutton". That should give you an idea about her appetite.
* ContinuityNod: The Knock Up Stream from the Jaya arc
* {{Expy}}: Lily, possibly of [[http://onepiece.wikia.com/wiki/Blyue Blyue]] from the ''Round The Land'' game who had the same fruit and was also a giant.
** If one is to include video games within the anime's timeline, this may mean that [[spoiler: Blyue has died, considering how Devil Fruits are reborn almost instantly after their user's death, and how two people can not have the same ability at a time]].
* DisproportionateRetribution: Granted Panz Fry is a decent pirate whose main crime was mostly stealing, so his getting shipped off to Impel Down makes sense. However Shuzo, who is part of Z's Neo Marines, wants to intercept and ''kill him'' entirely for this reason.
** However, considering Panz Fry's crime is not that terrible compared to other pirates', and how [[TheAlcatraz hardcore a prison Impel Down is]], one may still think that his being shipped off to it is DisproportionateRetribution in itself. Though it is mentioned that Panz Fry got caught raiding a Marine cargo ship which happened to have [[BadassNormal Momonga]] on it. So make of that what you will.
* DoomedByCanon: Considering Shuzo isn't in [[Anime/OnePieceFilmZ Film Z]], it's obvious from the start he's going to fail in killing Panz Fry.
* {{Foreshadowing}}: Shuzo brazenly lets a hint slip to Momonga about Z and the Neo Marines. Considering his troops' reactions, it was meant to be a secret and more than likely Momonga will report this to the other Marines later on.
* ImprobableWeaponUser: Lily uses a dinner fork, whose size changes along with her, as a spear.
* [[IncredibleShrinkingMan Incredible Shrinking Woman]]: Lily who ate the Mini Mini no Mi Fruit and can shrink to a smaller form with it.
** AttackOfTheFiftyFootWhatever: And when she's isn't using it, she's this.
** PintsizedPowerhouse: And she still retains her strength in mini mode too.
** GoodIsNotSoft: She claims one of the ways she can defeat her enemies is by slipping inside their body and then growing back to normal size, making the enemy burst into pieces. ''Damn, that's brutal''.
* JustLikeRobinHood: According to Lily, Panz Fry only stole food from Marines and other pirates to help those who are starving.
* LivingWeapon: Alpacacino, Shuzo's pet alpaca who can fire cannon blasts from his mouth. Par for the course, it's another weapon turned living being thanks to a Devil Fruit.
* MeleeATrois: Between the Straw Hats, Momonga and his Marine fleet and Shuzo and his Neo Marines fleet.
* NotSoDifferent: Luffy and Lily are incredibly similar, they pretty much hit it off right off the bat.
* TheStarscream: Shuzo is this not to Z, surprisingly, but to [[TheDragon Ain]].
* TheStoic: It seems Ain doesn't mess around when it comes to her job.
* SupremeChef: Panz Fry is mentioned to be one, using natural elements such as volcanos to cook his food.