Animation and live action footage mix together in this comedy adventure from directors Peter and Bobby Farrelly. When Frank (Bill Murray) eats a boiled egg tainted by monkey spit, an unwelcome virus is released into his body's animated interior. The body defends itself by placing tough cellular cop Osmosis Jones on the case, sending him chasing through the various channels of Frank's internal system in pursuit of the invader. Osmosis then teams up with a cold remedy called Drix and starts causing all kinds of havoc in his attempt to arrest the unruly virus. Meanwhile back on the outside world poor Frank is being sent into all kinds of agony by the battle raging deep within him.