Our company tracks plans of health services for consumers. For any given consumer the plans are consecutively numbered, starting with 1. Each plan has a begin date. I need to return a result set of service plan numbers and dates as follows:
Return the last (latest) 3 plans by plan date plus the next plan number (which will have a null date). For instance consumer A has 4 plans as follows

Plan #	Begin date
1	01/01/2001
2	01/01/2002
3	12/15/2002
4	12/01/2003

My result set should look like

Plan #	Begin date
5	null
4	12/01/2003
3	12/15/2002
2	01/01/2002

When I use a TOP statement with a union as follows

Select top 3
blah, blah
union
select next number
order by begin_date desc

I end up with

Plan #	Begin date
5	null
3	12/15/2002
2	01/01/2002
1	01/01/2001

Any ideas?

TIA
John