In ancient Kyoto two men are vying for beauty. One is Ikenobo Senkou, a connoisseur of flowers who is also a priest in charge of defending the Rokkakudo. He practices flower arrangement there everyday, presenting pleasing views for the people of the capital. The other one is Sen no Rikyū, a tea master. Formerly the tea server at Oda Nobunaga’s court, he becomes Toyotomi Hideyoshi's tea server after Oda's demise.

The people of Kyoto, despite their wretched state of penury and the constant threat of war, spend every day of their lives as happily as possible. The two men lead their prominent, exemplary lives amidst such a world, and even though their interests differ and they engage in a rivalry, as fellow pursuers of beauty, they are bound together by a deep friendship and mutual trust.

Hideyoshi has his own aesthetic values regarding tea, but as time passes his tastes begin to diverge from those of Rikyū. Consequently peaceful days end and Rikyū is ordered to commit seppuku (self disembowelment), having made Hideyoshi angry at last. Maeda Toshiie, the feudal lord of the Kaga clan who is sympathetic to Rikyū's views, intervenes and advises Rikyū to repent, saying, "Just one word of apology will do. You will at least save yourself from committing seppuku." Senkou also pleads, "Your life is priceless. Apologize!" But Rikyū refuses to budge, remaining defiant and choosing to die a violent death by his own sword.

Senkou falls into a state of desperate sadness, having lost not only his worthy rival, but also his dear friend. For a while he broods, overwhelmed by a sense of futility and hopelessness and is about to even give up his passion for flowers.

But what ends up saving Senkou is none other than the power of flowers itself. To avenge Rikyū’s death, he swears revenge on Toyotomi Hideyoshi. But he hesitates. The enemy is Toyotomi Hideyoshi, after all, a man who wields immense power. How could he retaliate against such a figure? Someone who is always surrounded by bodyguards?

From the moment Senkou begins to plot, innocent people around him begin to lose their lives. Senkou is consumed by rage, but one day a once-in-a-lifetime opportunity to exact revenge arrives. He comes to find out that Hideyoshi plans to visit the house of Maeda Toshiie.

Senkou requests to be allowed to arrange flowers there on the day of the visit. Maeda appreciates his thoughtfulness and gives him permission to do so. Senkou then goes on to successfully exact revenge, making Hideyoshi—the power that be—surrender without the use of any military force at all. In effect, he makes him surrender with just flowers. Hideyoshi now repents from the bottom of his heart for ever having mandated Rikyū to die by his own sword.

When you speak of the tea ceremony, Sen no Rikyū readily comes to mind. It attests to the fact that the art of tea and the art of flower arrangement are inextricably linked. Yet Senkou’s episode and the world of the Ikenobo art of flower arrangement remain in relative obscurity.

In retaliation against Hideyoshi, who threatens to use military force to have his way, Senkou battles against him with nothing more than his way of life: the way of flowers, a set of principles to which he has dedicated his entire life.

Based on a true story handed down to the headmaster of the Ikenobo school of flower arrangement, which has a 550-year history, Flower War is a moving story that tells the tale of men who defended their own principles of beauty and honor.

The option on the film rights to this work has been sold and production for its cinematic adaptation is currently underway with a nationwide release slated for 2015. In addition, the work has been adapted into a musical, which will embark on a nationwide tour in May, starting in Tokyo.

There are fans of flower arrangement and members of the Ikenobo school of flower arrangement all over the world.