1. A computer program embedded in a computer readable medium, comprising: a first program code module which controls an action of a player's character in a battle between the player's character and an enemy character; a second program code module which controls an action of the enemy character in the battle; a third program code module which stores, in a first point storage, a current value of a first point indicative of a power required for achieving a specific ability in the battle and manages an increase and decrease in the current value of the first point; and a fourth program code module which stores, in a second point storage, a current value of a second point indicative of a vitality of the player's character and the enemy character and manages an increase and decrease in the current value of the second point, wherein when one character attacks on the other character, said program code module which manages the increase and decrease in the current value of the second point subtracts a predetermined value, as a damage caused by the attack, from the current value of the second said program code module which manages the increase and decrease in the current value of the first point adds a value calculated according to the damage caused by the attack, to the current value of the first point, the first point stored in the first point storage is shared by the player's character and the enemy character, and when the player's character exercises the specific ability or the enemy character exercises the specific ability, said program code module which manages the change in the current value of the first point subtracts a value required for the exercise of the specific ability, from the current value of the first point; and wherein when an action has been executed by a first character and thereafter the first character is attacked by a second character during a time duration until the action by the first character is completed, said first program code module which controls the action of the player's character and said second program code module which controls the action of the enemy character cancel the action by the first character and when the first point in the first point storage has been reduced by the action by the first character, said first program code module which controls the action of the player's character and said second program code module which controls the action of the enemy character restore the value by adding an value equivalent to the amount subtracted.