▁A ▁s occer ▁ball ▁housing ▁bio - engine ered ▁b acter ia ▁which ▁continu ously ▁produce ▁a ▁gas ▁that ▁turns ▁any ▁who ▁in h ale ▁it ▁into ▁a ▁don key . ▁Due ▁to ▁a ▁slight ▁m ish ap ▁during ▁an ▁attempted ▁mid - air ▁hij ack ing ▁( since ▁the ▁plane ▁passengers ▁did ▁not ▁believe ▁that ▁the ▁terror ist ' s ▁hand ▁gr en ade ▁was ▁real ), ▁the ▁ball ▁instead ▁ends ▁up ▁near ▁the ▁Spanish ▁coast , ▁where ▁it ▁is ▁unw itting ly ▁picked ▁up ▁by ▁a ▁number ▁of ▁bo aters . ▁Since ▁the ▁ball ▁has ▁somehow ▁suffered ▁a ▁leak , ▁it ▁instantly ▁turns ▁its ▁find ers ▁into ▁don keys . ▁ ▁Once ▁the ▁T . I . A .' s ▁Super int endent ▁Vic ent ▁is ▁informed ▁of ▁the ▁situation , ▁he ▁assign s ▁Mort ad elo ▁and ▁File m ón ▁with ▁retr ieving ▁the ▁ball . ▁However , ▁since ▁the ▁ball ▁is ▁transferred ▁to ▁a ▁mult itude ▁of ▁different ▁places , ▁and ▁because ▁Mort ad elo ▁and ▁File m ón ▁handle ▁the ▁ball ▁somewhat ▁care lessly , ▁a ▁lot ▁of ▁innoc ent ▁people ▁- ▁including ▁Vic ente , ▁Of elia , ▁and ▁Professor ▁B acter io ▁- ▁are ▁turned ▁into ▁don keys ▁before ▁they ▁succeed . ▁While ▁Professor ▁B acter io ▁is ▁hard pressed ▁to ▁develop ▁an ▁effective ▁ant id ote ▁for ▁this ▁mal ady , ▁the ▁terror ist ▁band ▁repeatedly ▁attacks ▁the ▁T . I . A . ▁headquarters ▁in ▁order ▁to ▁get ▁the ▁ball ▁back ▁into ▁their ▁own